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The Z Shell Manual
******************

   This Info file documents Zsh, a freely available UNIX command
interpreter (shell), which of the standard shells most closely
resembles the Korn shell (ksh), although it is not completely
compatible.

Version 4.3.11, last updated December 20, 2010.

* Menu:

* The Z Shell Manual::
* Introduction::
* Roadmap::
* Invocation::
* Files::
* Shell Grammar::
* Redirection::
* Command Execution::
* Functions::
* Jobs & Signals::
* Arithmetic Evaluation::
* Conditional Expressions::
* Prompt Expansion::
* Expansion::
* Parameters::
* Options::
* Shell Builtin Commands::
* Zsh Line Editor::
* Completion Widgets::
* Completion System::
* Completion Using compctl::
* Zsh Modules::
* Calendar Function System::
* TCP Function System::
* Zftp Function System::
* User Contributions::

--- Indices ---

* Concept Index::
* Variables Index::
* Options Index::
* Functions Index::
* Editor Functions Index::
* Style and Tag Index::

--- The Detailed Node Listing ---

Introduction

* Author::
* Availability::
* Mailing Lists::
* The Zsh FAQ::
* The Zsh Web Page::
* The Zsh Userguide::
* See Also::

Roadmap

Invocation

* Compatibility::
* Restricted Shell::

Shell Grammar

* Simple Commands & Pipelines::
* Precommand Modifiers::
* Complex Commands::
* Alternate Forms For Complex Commands::
* Reserved Words::
* Comments::
* Aliasing::
* Quoting::

Expansion

* History Expansion::
* Process Substitution::
* Parameter Expansion::
* Command Substitution::
* Arithmetic Expansion::
* Brace Expansion::
* Filename Expansion::
* Filename Generation::

Parameters

* Array Parameters::
* Positional Parameters::
* Local Parameters::
* Parameters Set By The Shell::
* Parameters Used By The Shell::

Options

* Specifying Options::
* Description of Options::
* Option Aliases::
* Single Letter Options::

Zsh Line Editor

* Movement::
* History Control::
* Modifying Text::
* Arguments::
* Completion::
* Miscellaneous::

Completion Widgets

* Completion Special Parameters::
* Completion Builtin Commands::
* Completion Condition Codes::
* Completion Matching Control::
* Completion Widget Example::

Completion System

* Initialization::
* Completion System Configuration::
* Control Functions::
* Bindable Commands::
* Completion Functions::
* Completion Directories::

Completion Using compctl

* Command Flags::
* Option Flags::
* Alternative Completion::
* Extended Completion::
* Example::

Zsh Modules

* The zsh/attr Module::
* The zsh/cap Module::
* The zsh/clone Module::
* The zsh/compctl Module::
* The zsh/complete Module::
* The zsh/complist Module::
* The zsh/computil Module::
* The zsh/curses Module::
* The zsh/datetime Module::
* The zsh/deltochar Module::
* The zsh/example Module::
* The zsh/files Module::
* The zsh/mapfile Module::
* The zsh/mathfunc Module::
* The zsh/newuser Module::
* The zsh/parameter Module::
* The zsh/pcre Module::
* The zsh/regex Module::
* The zsh/sched Module::
* The zsh/net/socket Module::
* The zsh/stat Module::
* The zsh/system Module::
* The zsh/net/tcp Module::
* The zsh/termcap Module::
* The zsh/terminfo Module::
* The zsh/zftp Module::
* The zsh/zle Module::
* The zsh/zleparameter Module::
* The zsh/zprof Module::
* The zsh/zpty Module::
* The zsh/zselect Module::
* The zsh/zutil Module::

TCP Function System

* TCP Functions::
* TCP Parameters::
* TCP Examples::
* TCP Bugs::

Zftp Function System

* Installation::
* Zftp Functions::
* Miscellaneous Features::

User Contributions

* Utilities::
* Prompt Themes::
* ZLE Functions::
* Other Functions::

File: zsh.info,  Node: The Z Shell Manual,  Next: Introduction,  Prev: Top,  Up: Top

1 The Z Shell Manual
********************

This document has been produced from the texinfo file zsh.texi,
included in the Doc sub-directory of the Zsh distribution.

1.1 Producing documentation from zsh.texi
=========================================

The texinfo source may be converted into several formats:


The Info manual
     The Info format allows searching for topics, commands, functions,
     etc.  from the many Indices. The command `makeinfo zsh.texi' is
     used to produce the Info documentation.

The printed manual
     The command `texi2dvi zsh.texi' will output zsh.dvi which can then
     be processed with `dvips' and optionally `gs' (Ghostscript) to
     produce a nicely formatted printed manual.

The HTML manual
     An HTML version of this manual is available at the Zsh web site
     via:

     http://zsh.sourceforge.net/Doc/.

     (The HTML version is produced with `texi2html', which may be
     obtained from http://www.nongnu.org/texi2html/. The command is
     `texi2html -output .  -ifinfo -split=chapter -node-files zsh.texi'.
     If necessary, upgrade to version 1.78 of texi2html.)


For those who do not have the necessary tools to process texinfo,
precompiled documentation (PostScript, dvi, info and HTML formats) is
available from the zsh archive site or its mirrors, in the file
zsh-doc.tar.gz. (See *note Availability:: for a list of sites.)

File: zsh.info,  Node: Introduction,  Next: Roadmap,  Prev: The Z Shell Manual,  Up: Top

2 Introduction
**************

Zsh is a UNIX command interpreter (shell) usable as an interactive
login shell and as a shell script command processor.  Of the standard
shells, zsh most closely resembles `ksh' but includes many
enhancements.  Zsh has command line editing, builtin spelling
correction, programmable command completion, shell functions (with
autoloading), a history mechanism, and a host of other features.

* Menu:

* Author::
* Availability::
* Mailing Lists::
* The Zsh FAQ::
* The Zsh Web Page::
* The Zsh Userguide::
* See Also::

File: zsh.info,  Node: Author,  Next: Availability,  Up: Introduction

2.1 Author
==========

Zsh was originally written by Paul Falstad <pfATzsh.org>.  Zsh is now
maintained by the members of the zsh-workers mailing list
<zsh-workersATzsh.org>.  The development is currently coordinated by
Peter Stephenson <pwsATzsh.org>.  The coordinator can be contacted at
<coordinatorATzsh.org>, but matters relating to the code should
generally go to the mailing list.

File: zsh.info,  Node: Availability,  Next: Mailing Lists,  Prev: Author,  Up: Introduction

2.2 Availability
================

Zsh is available from the following anonymous FTP sites.  These mirror
sites are kept frequently up to date.  The sites marked with _(H)_ may
be mirroring ftp.cs.elte.hu instead of the primary site.


Primary site
     ftp://ftp.zsh.org/pub/zsh/
     http://www.zsh.org/pub/zsh/

Australia
     ftp://ftp.zsh.org/pub/zsh/
     http://www.zsh.org/pub/zsh/

Finland
     ftp://ftp.funet.fi/pub/unix/shells/zsh/

Germany
     ftp://ftp.fu-berlin.de/pub/unix/shells/zsh/  _(H)_
     ftp://ftp.gmd.de/packages/zsh/
     ftp://ftp.uni-trier.de/pub/unix/shell/zsh/

Hungary
     ftp://ftp.cs.elte.hu/pub/zsh/
     http://www.cs.elte.hu/pub/zsh/
     ftp://ftp.kfki.hu/pub/packages/zsh/

Israel
     ftp://ftp.math.technion.ac.il/pub/zsh/
     http://www.math.technion.ac.il/pub/zsh/

Japan
     ftp://ftp.win.ne.jp/pub/shell/zsh/

Korea
     ftp://linux.sarang.net/mirror/system/shell/zsh/

Netherlands
     ftp://ftp.demon.nl/pub/mirrors/zsh/

Norway
     ftp://ftp.uit.no/pub/unix/shells/zsh/

Poland
     ftp://sunsite.icm.edu.pl/pub/unix/shells/zsh/

Romania
     ftp://ftp.roedu.net/pub/mirrors/ftp.zsh.org/pub/zsh/
     ftp://ftp.kappa.ro/pub/mirrors/ftp.zsh.org/pub/zsh/

Slovenia
     ftp://ftp.siol.net/mirrors/zsh/

Sweden
     ftp://ftp.lysator.liu.se/pub/unix/zsh/

UK
     ftp://ftp.net.lut.ac.uk/zsh/
     ftp://sunsite.org.uk/packages/zsh/

USA
     http://zsh.open-mirror.com/


The up-to-date source code is available via anonymous CVS and Git from
Sourceforge.  See http://sourceforge.net/projects/zsh/ for details.  A
summary of instructions for the CVS and Git archives can be found at
http://zsh.sourceforget.net/.



File: zsh.info,  Node: Mailing Lists,  Next: The Zsh FAQ,  Prev: Availability,  Up: Introduction

2.3 Mailing Lists
=================

Zsh has 3 mailing lists:


<zsh-announceATzsh.org>
     Announcements about releases, major changes in the shell and the
     monthly posting of the Zsh FAQ.  (moderated)

<zsh-usersATzsh.org>
     User discussions.

<zsh-workersATzsh.org>
     Hacking, development, bug reports and patches.


To subscribe or unsubscribe, send mail to the associated administrative
address for the mailing list.


<zsh-announce-subscribeATzsh.org>

<zsh-users-subscribeATzsh.org>

<zsh-workers-subscribeATzsh.org>


<zsh-announce-unsubscribeATzsh.org>

<zsh-users-unsubscribeATzsh.org>

<zsh-workers-unsubscribeATzsh.org>


YOU ONLY NEED TO JOIN ONE OF THE MAILING LISTS AS THEY ARE NESTED.  All
submissions to `zsh-announce' are automatically forwarded to
`zsh-users'.  All submissions to `zsh-users' are automatically
forwarded to `zsh-workers'.

If you have problems subscribing/unsubscribing to any of the mailing
lists, send mail to <listmasterATzsh.org>.  The mailing lists are
maintained by Karsten Thygesen <karthyATkom.dk>.

The mailing lists are archived; the archives can be accessed via the
administrative addresses listed above.  There is also a hypertext
archive, maintained by Geoff Wing <gcwATzsh.org>, available at
http://www.zsh.org/mla/.

File: zsh.info,  Node: The Zsh FAQ,  Next: The Zsh Web Page,  Prev: Mailing Lists,  Up: Introduction

2.4 The Zsh FAQ
===============

Zsh has a list of Frequently Asked Questions (FAQ), maintained by Peter
Stephenson <pwsATzsh.org>.  It is regularly posted to the newsgroup
`comp.unix.shell' and the `zsh-announce' mailing list.  The latest
version can be found at any of the Zsh FTP sites, or at
http://www.zsh.org/FAQ/.  The contact address for FAQ-related matters
is <faqmasterATzsh.org>.

File: zsh.info,  Node: The Zsh Web Page,  Next: The Zsh Userguide,  Prev: The Zsh FAQ,  Up: Introduction

2.5 The Zsh Web Page
====================

Zsh has a web page which is located at http://www.zsh.org/.  This is
maintained by Karsten Thygesen <karthyATzsh.org>, of SunSITE Denmark.
The contact address for web-related matters is <webmasterATzsh.org>.

File: zsh.info,  Node: The Zsh Userguide,  Next: See Also,  Prev: The Zsh Web Page,  Up: Introduction

2.6 The Zsh Userguide
=====================

A userguide is currently in preparation.  It is intended to complement
the manual, with explanations and hints on issues where the manual can
be cabbalistic, hierographic, or downright mystifying (for example, the
word `hierographic' does not exist).  It can be viewed in its current
state at http://zsh.sourceforge.net/Guide/.  At the time of writing,
chapters dealing with startup files and their contents and the new
completion system were essentially complete.

2.7 The Zsh Wiki
================

A `wiki' website for zsh has been created at http://www.zshwiki.org/.
This is a site which can be added to and modified directly by users
without any special permission.  You can add your own zsh tips and
configurations.

File: zsh.info,  Node: See Also,  Prev: The Zsh Userguide,  Up: Introduction

2.8 See Also
============

man page sh(1), man page csh(1), man page tcsh(1), man page rc(1), man
page bash(1), man page ksh(1)

`IEEE Standard for information Technology - Portable Operating System
Interface (POSIX) - Part 2: Shell and Utilities', IEEE Inc, 1993, ISBN
1-55937-255-9.

File: zsh.info,  Node: Roadmap,  Next: Invocation,  Prev: Introduction,  Up: Top

3 Roadmap
*********



The Zsh Manual, like the shell itself, is large and often complicated.
This section of the manual provides some pointers to areas of the shell
that are likely to be of particular interest to new users, and indicates
where in the rest of the manual the documentation is to be found.



3.1 When the shell starts
=========================

When it starts, the shell reads commands from various files.  These can
be created or edited to customize the shell.  See *note Files::.

If no personal initialization files exist for the current user, a
function is run to help you change some of the most common settings.
It won't appear if your administrator has disabled the zsh/newuser
module.  The function is designed to be self-explanatory.  You can run
it by hand with `autoload -Uz zsh-newuser-install; zsh-newuser-install
-f'.  See also *note User Configuration Functions::.



3.2 Interactive Use
===================

Interaction with the shell uses the builtin Zsh Line Editor, ZLE.  This
is described in detail in *note Zsh Line Editor::.

The first decision a user must make is whether to use the Emacs or Vi
editing mode as the keys for editing are substantially different.  Emacs
editing mode is probably more natural for beginners and can be selected
explicitly with the command bindkey -e.

A history mechanism for retrieving previously typed lines (most simply
with the Up or Down arrow keys) is available; note that, unlike other
shells, zsh will not save these lines when the shell exits unless you
set appropriate variables, and the number of history lines retained by
default is quite small (30 lines).  See the description of the shell
variables (referred to in the documentation as parameters) HISTFILE,
HISTSIZE and SAVEHIST in *note Parameters Used By The Shell::.

The shell now supports the UTF-8 character set (and also others if
supported by the operating system).  This is (mostly) handled
transparently by the shell, but the degree of support in terminal
emulators is variable.  There is some discussion of this in the shell
FAQ, http://zsh.dotsrc.org/FAQ/ .  Note in particular that for combining
characters to be handled the option COMBINING_CHARS needs to be set.
Because the shell is now more sensitive to the definition of the
character set, note that if you are upgrading from an older version of
the shell you should ensure that the appropriate variable, either LANG
(to affect all aspects of the shell's operation) or LC_CTYPE (to affect
only the handling of character sets) is set to an appropriate value.
This is true even if you are using a single-byte character set
including extensions of ASCII such as ISO-8859-1 or ISO-8859-15.  See
the description of LC_CTYPE in *note Parameters::.



3.2.1 Completion
----------------

Completion is a feature present in many shells. It allows the user to
type only a part (usually the prefix) of a word and have the shell fill
in the rest.  The completion system in zsh is programmable.  For
example, the shell can be set to complete email addresses in arguments
to the mail command from your ~/.abook/addressbook; usernames,
hostnames, and even remote paths in arguments to scp, and so on.
Anything that can be written in or glued together with zsh can be the
source of what the line editor offers as possible completions.

Zsh has two completion systems, an old, so called compctl completion
(named after the builtin command that serves as its complete and only
user interface), and a new one, referred to as compsys, organized as
library of builtin and user-defined functions.  The two systems differ
in their interface for specifying the completion behavior.  The new
system is more customizable and is supplied with completions for many
commonly used commands; it is therefore to be preferred.

The completion system must be enabled explicitly when the shell starts.
For more information see *note Completion System::.



3.2.2 Extending the line editor
-------------------------------

Apart from completion, the line editor is highly extensible by means of
shell functions.  Some useful functions are provided with the shell;
they provide facilities such as:


insert-composed-char
     composing characters not found on the keyboard

match-words-by-style
     configuring what the line editor considers a word when moving or
     deleting by word

history-beginning-search-backward-end, etc.
     alternative ways of searching the shell history

replace-string, replace-pattern
     functions for replacing strings or patterns globally in the
     command line

edit-command-line
     edit the command line with an external editor.


See *note ZLE Functions:: for descriptions of these.



3.3 Options
===========

The shell has a large number of options for changing its behaviour.
These cover all aspects of the shell; browsing the full documentation is
the only good way to become acquainted with the many possibilities.  See
*note Options::.



3.4 Pattern Matching
====================

The shell has a rich set of patterns which are available for file
matching (described in the documentation as `filename generation' and
also known for historical reasons as `globbing') and for use when
programming.  These are described in *note Filename Generation::.

Of particular interest are the following patterns that are not commonly
supported by other systems of pattern matching:


**
     for matching over multiple directories

~, ^
     the ability to exclude patterns from matching when the
     EXTENDED_GLOB option is set

(...)
     glob qualifiers, included in parentheses at the end of the pattern,
     which select files by type (such as directories) or attribute
     (such as size).



3.5 General Comments on Syntax
==============================

Although the syntax of zsh is in ways similar to the Korn shell, and
therefore more remotely to the original UNIX shell, the Bourne shell,
its default behaviour does not entirely correspond to those shells.
General shell syntax is introduced in *note Shell Grammar::.

One commonly encountered difference is that variables substituted onto
the command line are not split into words.  See the description of the
shell option SH_WORD_SPLIT in *note Parameter Expansion::.  In zsh, you
can either explicitly request the splitting (e.g. ${=foo}) or use an
array when you want a variable to expand to more than one word.  See
*note Array Parameters::.



3.6 Programming
===============

The most convenient way of adding enhancements to the shell is typically
by writing a shell function and arranging for it to be autoloaded.
Functions are described in *note Functions::.  Users changing from the
C shell and its relatives should notice that aliases are less used in
zsh as they don't perform argument substitution, only simple text
replacement.

A few general functions, other than those for the line editor described
above, are provided with the shell and are described in *note User
Contributions::.  Features include:


promptinit
     a prompt theme system for changing prompts easily, see *note
     Prompt Themes::

zsh-mime-setup
     a MIME-handling system which dispatches commands according to the
     suffix of a file as done by graphical file managers

zcalc
     a calculator

zargs
     a version of xargs that makes the find command redundant

zmv
     a command for renaming files by means of shell patterns.


File: zsh.info,  Node: Invocation,  Next: Files,  Prev: Roadmap,  Up: Top

4 Invocation
************



4.1 Invocation
==============

The following flags are interpreted by the shell when invoked to
determine where the shell will read commands from:


-c
     Take the first argument as a command to execute, rather than
     reading commands from a script or standard input.  If any further
     arguments are given, the first one is assigned to $0, rather than
     being used as a positional parameter.

-i
     Force shell to be interactive.  It is still possible to specify a
     script to execute.

-s
     Force shell to read commands from the standard input.  If the -s
     flag is not present and an argument is given, the first argument
     is taken to be the pathname of a script to execute.


If there are any remaining arguments after option processing, and
neither of the options -c or -s was supplied, the first argument is
taken as the file name of a script containing shell commands to be
executed.  If the option PATH_SCRIPT is set, and the file name does not
contain a directory path (i.e. there is no `/' in the name), first the
current directory and then the command path given by the variable PATH
are searched for the script.  If the option is not set or the file name
contains a `/' it is used directly.

After the first one or two arguments have been appropriated as
described above, the remaining arguments are assigned to the positional
parameters.

For further options, which are common to invocation and the set
builtin, see *note Options::.

Options may be specified by name using the -o option.  -o acts like a
single-letter option, but takes a following string as the option name.
For example,


     zsh -x -o shwordsplit scr

runs the script scr, setting the XTRACE option by the corresponding
letter `-x' and the SH_WORD_SPLIT option by name.  Options may be
turned _off_ by name by using +o instead of -o.  -o can be stacked up
with preceding single-letter options, so for example `-xo shwordsplit'
or `-xoshwordsplit' is equivalent to `-x -o shwordsplit'.

Options may also be specified by name in GNU long option style,
`--OPTION-NAME'.  When this is done, `-' characters in the option name
are permitted: they are translated into `_', and thus ignored.  So, for
example, `zsh --sh-word-split' invokes zsh with the SH_WORD_SPLIT
option turned on.  Like other option syntaxes, options can be turned
off by replacing the initial `-' with a `+'; thus `+-sh-word-split' is
equivalent to `--no-sh-word-split'.  Unlike other option syntaxes,
GNU-style long options cannot be stacked with any other options, so for
example `-x-shwordsplit' is an error, rather than being treated like
`-x --shwordsplit'.

The special GNU-style option `--version' is handled; it sends to
standard output the shell's version information, then exits
successfully.  `--help' is also handled; it sends to standard output a
list of options that can be used when invoking the shell, then exits
successfully.

Option processing may be finished, allowing following arguments that
start with `-' or `+' to be treated as normal arguments, in two ways.
Firstly, a lone `-' (or `+') as an argument by itself ends option
processing.  Secondly, a special option `--' (or `+-'), which may be
specified on its own (which is the standard POSIX usage) or may be
stacked with preceding options (so `-x-' is equivalent to `-x --').
Options are not permitted to be stacked after `--' (so `-x-f' is an
error), but note the GNU-style option form discussed above, where
`--shwordsplit' is permitted and does not end option processing.

Except when the `sh'/`ksh' emulation single-letter options are in
effect, the option `-b' (or `+b') ends option processing.  `-b' is like
`--', except that further single-letter options can be stacked after
the `-b' and will take effect as normal.



* Menu:

* Compatibility::
* Restricted Shell::


File: zsh.info,  Node: Compatibility,  Next: Restricted Shell,  Up: Invocation

4.2 Compatibility
=================

Zsh tries to emulate `sh' or `ksh' when it is invoked as sh or ksh
respectively; more precisely, it looks at the first letter of the name
by which it was invoked, excluding any initial `r' (assumed to stand
for `restricted'), and if that is `s' or `k' it will emulate `sh' or
`ksh'.  Furthermore, if invoked as su (which happens on certain systems
when the shell is executed by the su command), the shell will try to
find an alternative name from the SHELL environment variable and
perform emulation based on that.

In `sh' and `ksh' compatibility modes the following parameters are not
special and not initialized by the shell: ARGC, argv, cdpath, fignore,
fpath, HISTCHARS, mailpath, MANPATH, manpath, path, prompt, PROMPT,
PROMPT2, PROMPT3, PROMPT4, psvar, status, watch.

The usual zsh startup/shutdown scripts are not executed.  Login shells
source /etc/profile followed by $HOME/.profile.  If the ENV environment
variable is set on invocation, $ENV is sourced after the profile
scripts.  The value of ENV is subjected to parameter expansion, command
substitution, and arithmetic expansion before being interpreted as a
pathname.  Note that the PRIVILEGED option also affects the execution
of startup files.

The following options are set if the shell is invoked as sh or ksh:
NO_BAD_PATTERN, NO_BANG_HIST, NO_BG_NICE, NO_EQUALS,
NO_FUNCTION_ARGZERO, GLOB_SUBST, NO_GLOBAL_EXPORT, NO_HUP,
INTERACTIVE_COMMENTS, KSH_ARRAYS, NO_MULTIOS, NO_NOMATCH, NO_NOTIFY,
POSIX_BUILTINS, NO_PROMPT_PERCENT, RM_STAR_SILENT, SH_FILE_EXPANSION,
SH_GLOB, SH_OPTION_LETTERS, SH_WORD_SPLIT.  Additionally the BSD_ECHO
and IGNORE_BRACES options are set if zsh is invoked as sh.  Also, the
KSH_OPTION_PRINT, LOCAL_OPTIONS, PROMPT_BANG, PROMPT_SUBST and
SINGLE_LINE_ZLE options are set if zsh is invoked as ksh.

File: zsh.info,  Node: Restricted Shell,  Prev: Compatibility,  Up: Invocation

4.3 Restricted Shell
====================

When the basename of the command used to invoke zsh starts with the
letter `r' or the `-r' command line option is supplied at invocation,
the shell becomes restricted.  Emulation mode is determined after
stripping the letter `r' from the invocation name.  The following are
disabled in restricted mode:


   * changing directories with the cd builtin

   * changing or unsetting the PATH, path, MODULE_PATH, module_path,
     SHELL, HISTFILE, HISTSIZE, GID, EGID, UID, EUID, USERNAME,
     LD_LIBRARY_PATH, LD_AOUT_LIBRARY_PATH, LD_PRELOAD and
     LD_AOUT_PRELOAD parameters

   * specifying command names containing /

   * specifying command pathnames using hash

   * redirecting output to files

   * using the exec builtin command to replace the shell with another
     command

   * using jobs -Z to overwrite the shell process' argument and
     environment space

   * using the ARGV0 parameter to override argv[0] for external commands

   * turning off restricted mode with set +r or unsetopt RESTRICTED

These restrictions are enforced after processing the startup files.  The
startup files should set up PATH to point to a directory of commands
which can be safely invoked in the restricted environment.  They may
also add further restrictions by disabling selected builtins.

Restricted mode can also be activated any time by setting the
RESTRICTED option.  This immediately enables all the restrictions
described above even if the shell still has not processed all startup
files.

File: zsh.info,  Node: Files,  Next: Shell Grammar,  Prev: Invocation,  Up: Top

5 Files
*******



5.1 Startup/Shutdown Files
==========================

Commands are first read from /etc/zshenv; this cannot be overridden.
Subsequent behaviour is modified by the RCS and GLOBAL_RCS options; the
former affects all startup files, while the second only affects global
startup files (those shown here with an path starting with a /).  If
one of the options is unset at any point, any subsequent startup file(s)
of the corresponding type will not be read.  It is also possible for a
file in $ZDOTDIR to re-enable GLOBAL_RCS. Both RCS and GLOBAL_RCS are
set by default.

Commands are then read from $ZDOTDIR/.zshenv.  If the shell is a login
shell, commands are read from /etc/zprofile and then $ZDOTDIR/.zprofile.  Then,
if the shell is interactive, commands are read from /etc/zshrc and then
$ZDOTDIR/.zshrc.  Finally, if the shell is a login shell, /etc/zlogin
and $ZDOTDIR/.zlogin are read.

When a login shell exits, the files $ZDOTDIR/.zlogout and then
/etc/zlogout are read.  This happens with either an explicit exit via
the exit or logout commands, or an implicit exit by reading end-of-file
from the terminal.  However, if the shell terminates due to exec'ing
another process, the logout files are not read.  These are also
affected by the RCS and GLOBAL_RCS options.  Note also that the RCS
option affects the saving of history files, i.e. if RCS is unset when
the shell exits, no history file will be saved.

If ZDOTDIR is unset, HOME is used instead.  Files listed above as being
in /etc may be in another directory, depending on the installation.

As /etc/zshenv is run for all instances of zsh, it is important that it
be kept as small as possible.  In particular, it is a good idea to put
code that does not need to be run for every single shell behind a test
of the form `if [[ -o rcs ]]; then ...' so that it will not be executed
when zsh is invoked with the `-f' option.

5.2 Files
=========


$ZDOTDIR/.zshenv

$ZDOTDIR/.zprofile

$ZDOTDIR/.zshrc

$ZDOTDIR/.zlogin

$ZDOTDIR/.zlogout

${TMPPREFIX}*   (default is /tmp/zsh*)

/etc/zshenv

/etc/zprofile

/etc/zshrc

/etc/zlogin

/etc/zlogout    (installation-specific - /etc is the default)


Any of these files may be pre-compiled with the zcompile builtin
command (*note Shell Builtin Commands::).  If a compiled file exists
(named for the original file plus the .zwc extension) and it is newer
than the original file, the compiled file will be used instead.

File: zsh.info,  Node: Shell Grammar,  Next: Redirection,  Prev: Files,  Up: Top

6 Shell Grammar
***************



* Menu:

* Simple Commands & Pipelines::
* Precommand Modifiers::
* Complex Commands::
* Alternate Forms For Complex Commands::
* Reserved Words::
* Comments::
* Aliasing::
* Quoting::

File: zsh.info,  Node: Simple Commands & Pipelines,  Next: Precommand Modifiers,  Up: Shell Grammar

6.1 Simple Commands & Pipelines
===============================

A _simple command_ is a sequence of optional parameter assignments
followed by blank-separated words, with optional redirections
interspersed.  The first word is the command to be executed, and the
remaining words, if any, are arguments to the command.  If a command
name is given, the parameter assignments modify the environment of the
command when it is executed.  The value of a simple command is its exit
status, or 128 plus the signal number if terminated by a signal.  For
example,


     echo foo

is a simple command with arguments.

A _pipeline_ is either a simple command, or a sequence of two or more
simple commands where each command is separated from the next by `|' or
`|&'.  Where commands are separated by `|', the standard output of the
first command is connected to the standard input of the next.  `|&' is
shorthand for `2>&1 |', which connects both the standard output and the
standard error of the command to the standard input of the next.  The
value of a pipeline is the value of the last command, unless the
pipeline is preceded by `!' in which case the value is the logical
inverse of the value of the last command.  For example,


     echo foo | sed 's/foo/bar/'

is a pipeline, where the output (`foo' plus a newline) of the first
command will be passed to the input of the second.

If a pipeline is preceded by `coproc', it is executed as a coprocess; a
two-way pipe is established between it and the parent shell.  The shell
can read from or write to the coprocess by means of the `>&p' and `<&p'
redirection operators or with `print -p' and `read -p'.  A pipeline
cannot be preceded by both `coproc' and `!'.  If job control is active,
the coprocess can be treated in other than input and output as an
ordinary background job.

A _sublist_ is either a single pipeline, or a sequence of two or more
pipelines separated by `&&' or `||'.  If two pipelines are separated by
`&&', the second pipeline is executed only if the first succeeds
(returns a zero status).  If two pipelines are separated by `||', the
second is executed only if the first fails (returns a nonzero status).
Both operators have equal precedence and are left associative.  The
value of the sublist is the value of the last pipeline executed.  For
example,


     dmesg | grep panic && print yes

is a sublist consisting of two pipelines, the second just a simple
command which will be executed if and only if the grep command returns
a zero status.  If it does not, the value of the sublist is that return
status, else it is the status returned by the print (almost certainly
zero).

A _list_ is a sequence of zero or more sublists, in which each sublist
is terminated by `;', `&', `&|', `&!', or a newline.  This terminator
may optionally be omitted from the last sublist in the list when the
list appears as a complex command inside `(...)'  or `{...}'.  When a
sublist is terminated by `;' or newline, the shell waits for it to
finish before executing the next sublist.  If a sublist is terminated
by a `&', `&|', or `&!', the shell executes the last pipeline in it in
the background, and does not wait for it to finish (note the difference
from other shells which execute the whole sublist in the background).
A backgrounded pipeline returns a status of zero.

More generally, a list can be seen as a set of any shell commands
whatsoever, including the complex commands below; this is implied
wherever the word `list' appears in later descriptions.  For example,
the commands in a shell function form a special sort of list.

File: zsh.info,  Node: Precommand Modifiers,  Next: Complex Commands,  Prev: Simple Commands & Pipelines,  Up: Shell Grammar

6.2 Precommand Modifiers
========================

A simple command may be preceded by a _precommand modifier_, which will
alter how the command is interpreted.  These modifiers are shell
builtin commands with the exception of nocorrect which is a reserved
word.


-
     The command is executed with a `-' prepended to its argv[0] string.

builtin
     The command word is taken to be the name of a builtin command,
     rather than a shell function or external command.

command [ -pvV ]
     The command word is taken to be the name of an external command,
     rather than a shell function or builtin.   If the POSIX_BUILTINS
     option is set, builtins will also be executed but certain special
     properties of them are suppressed. The -p flag causes a default
     path to be searched instead of that in $path. With the -v flag,
     command is similar to whence and with -V, it is equivalent to
     whence -v.

exec [ -cl ] [ -a ARGV0 ]
     The following command together with any arguments is run in place
     of the current process, rather than as a sub-process.  The shell
     does not fork and is replaced.  The shell does not invoke
     TRAPEXIT, nor does it source zlogout files.  The options are
     provided for compatibility with other shells.

     The -c option clears the environment.

     The -l option is equivalent to the - precommand modifier, to treat
     the replacement command as a login shell; the command is executed
     with a - prepended to its argv[0] string.  This flag has no effect
     if used together with the -a option.

     The -a option is used to specify explicitly the argv[0] string
     (the name of the command as seen by the process itself) to be used
     by the replacement command and is directly equivalent to setting a
     value for the ARGV0 environment variable.

nocorrect
     Spelling correction is not done on any of the words.  This must
     appear before any other precommand modifier, as it is interpreted
     immediately, before any parsing is done.  It has no effect in
     non-interactive shells.

noglob
     Filename generation (globbing) is not performed on any of the
     words.


File: zsh.info,  Node: Complex Commands,  Next: Alternate Forms For Complex Commands,  Prev: Precommand Modifiers,  Up: Shell Grammar

6.3 Complex Commands
====================

A _complex command_ in zsh is one of the following:


if LIST then LIST [ elif LIST then LIST ] ... [ else LIST ] fi
     The if LIST is executed, and if it returns a zero exit status, the
     then LIST is executed.  Otherwise, the elif LIST is executed and
     if its status is zero, the then LIST is executed.  If each elif
     LIST returns nonzero status, the else LIST is executed.

for NAME ... [ in WORD ... ] TERM do LIST done
     where TERM is at least one newline or ;.  Expand the list of
     WORDs, and set the parameter NAME to each of them in turn,
     executing LIST each time.  If the in WORD is omitted, use the
     positional parameters instead of the WORDs.

     More than one parameter NAME can appear before the list of WORDs.
     If N NAMEs are given, then on each execution of the loop the next
     N WORDs are assigned to the corresponding parameters.  If there
     are more NAMEs than remaining WORDs, the remaining parameters are
     each set to the empty string.  Execution of the loop ends when
     there is no remaining WORD to assign to the first NAME.  It is
     only possible for in to appear as the first NAME in the list, else
     it will be treated as marking the end of the list.

for (( [EXPR1] ; [EXPR2] ; [EXPR3] )) do LIST done
     The arithmetic expression EXPR1 is evaluated first (see *note
     Arithmetic Evaluation::).  The arithmetic expression EXPR2 is
     repeatedly evaluated until it evaluates to zero and when non-zero,
     LIST is executed and the arithmetic expression EXPR3 evaluated.
     If any expression is omitted, then it behaves as if it evaluated
     to 1.

while LIST do LIST done
     Execute the do LIST as long as the while LIST returns a zero exit
     status.

until LIST do LIST done
     Execute the do LIST as long as until LIST returns a nonzero exit
     status.

repeat WORD do LIST done
     WORD is expanded and treated as an arithmetic expression, which
     must evaluate to a number N.  LIST is then executed N times.

     The repeat syntax is disabled by default when the shell starts in
     a mode emulating another shell.  It can be enabled with the
     command `enable -r repeat'

case WORD in [ [(] PATTERN [ | PATTERN ] ... ) LIST (;;|;&|;|) ] ... esac
     Execute the LIST associated with the first PATTERN that matches
     WORD, if any.  The form of the patterns is the same as that used
     for filename generation.  See *note Filename Generation::.

     If the LIST that is executed is terminated with ;& rather than ;;,
     the following list is also executed.  The rule for the terminator
     of the following list ;;, ;& or ;| is applied unless the esac is
     reached.

     If the LIST that is executed is terminated with ;| the shell
     continues to scan the PATTERNs looking for the next match,
     executing the corresponding LIST, and applying the rule for the
     corresponding terminator ;;, ;& or ;|.  Note that WORD is not
     re-expanded; all applicable PATTERNs are tested with the same WORD.

select NAME [ in WORD ... TERM ] do LIST done
     where TERM is one or more newline or ; to terminate the WORDs.  Print
     the set of WORDs, each preceded by a number.  If the in WORD is
     omitted, use the positional parameters.  The PROMPT3 prompt is
     printed and a line is read from the line editor if the shell is
     interactive and that is active, or else standard input.  If this
     line consists of the number of one of the listed WORDs, then the
     parameter NAME is set to the WORD corresponding to this number.
     If this line is empty, the selection list is printed again.
     Otherwise, the value of the parameter NAME is set to null.  The
     contents of the line read from standard input is saved in the
     parameter REPLY.  LIST is executed for each selection until a
     break or end-of-file is encountered.

( LIST )
     Execute LIST in a subshell.  Traps set by the trap builtin are
     reset to their default values while executing LIST.

{ LIST }
     Execute LIST.

{ TRY-LIST } always { ALWAYS-LIST }
     First execute TRY-LIST.  Regardless of errors, or break, continue,
     or return commands encountered within TRY-LIST, execute
     ALWAYS-LIST.  Execution then continues from the result of the
     execution of TRY-LIST; in other words, any error, or break,
     continue, or return command is treated in the normal way, as if
     ALWAYS-LIST were not present.  The two chunks of code are referred
     to as the `try block' and the `always block'.

     Optional newlines or semicolons may appear after the always; note,
     however, that they may _not_ appear between the preceding closing
     brace and the always.

     An `error' in this context is a condition such as a syntax error
     which causes the shell to abort execution of the current function,
     script, or list.  Syntax errors encountered while the shell is
     parsing the code do not cause the ALWAYS-LIST to be executed.  For
     example, an erroneously constructed if block in try-list would
     cause the shell to abort during parsing, so that always-list would
     not be executed, while an erroneous substitution such as ${*foo*}
     would cause a run-time error, after which always-list would be
     executed.

     An error condition can be tested and reset with the special integer
     variable TRY_BLOCK_ERROR.  Outside an always-list the value is
     irrelevant, but it is initialised to -1.  Inside always-list, the
     value is 1 if an error occurred in the try-list, else 0.  If
     TRY_BLOCK_ERROR is set to 0 during the always-list, the error
     condition caused by the try-list is reset, and shell execution
     continues normally after the end of always-list.  Altering the
     value during the try-list is not useful (unless this forms part of
     an enclosing always block).

     Regardless of TRY_BLOCK_ERROR, after the end of always-list the
     normal shell status $? is the value returned from always-list.
     This will be non-zero if there was an error, even if
     TRY_BLOCK_ERROR was set to zero.

     The following executes the given code, ignoring any errors it
     causes.  This is an alternative to the usual convention of
     protecting code by executing it in a subshell.


          {
              # code which may cause an error
            } always {
              # This code is executed regardless of the error.
              (( TRY_BLOCK_ERROR = 0 ))
          }
          # The error condition has been reset.

     An exit command (or a return command executed at the outermost
     function level of a script) encountered in try-list does _not_
     cause the execution of ALWAYS-LIST.  Instead, the shell exits
     immediately after any EXIT trap has been executed.

function WORD ... [ () ] [ TERM ] { LIST }
WORD ... () [ TERM ] { LIST }
WORD ... () [ TERM ] COMMAND
     where TERM is one or more newline or ;.  Define a function which
     is referenced by any one of WORD.  Normally, only one WORD is
     provided; multiple WORDs are usually only useful for setting traps.
     The body of the function is the LIST between the { and }.  See
     *note Functions::.

     If the option SH_GLOB is set for compatibility with other shells,
     then whitespace may appear between between the left and right
     parentheses when there is a single WORD;  otherwise, the
     parentheses will be treated as forming a globbing pattern in that
     case.

time [ PIPELINE ]
     The PIPELINE is executed, and timing statistics are reported on
     the standard error in the form specified by the TIMEFMT parameter.
     If PIPELINE is omitted, print statistics about the shell process
     and its children.

[[ EXP ]]
     Evaluates the conditional expression EXP and return a zero exit
     status if it is true.  See *note Conditional Expressions:: for a
     description of EXP.


File: zsh.info,  Node: Alternate Forms For Complex Commands,  Next: Reserved Words,  Prev: Complex Commands,  Up: Shell Grammar

6.4 Alternate Forms For Complex Commands
========================================

Many of zsh's complex commands have alternate forms.  These are
non-standard and are likely not to be obvious even to seasoned shell
programmers; they should not be used anywhere that portability of shell
code is a concern.

The short versions below only work if SUBLIST is of the form `{ LIST }'
or if the SHORT_LOOPS option is set.  For the if, while and until
commands, in both these cases the test part of the loop must also be
suitably delimited, such as by `[[ ... ]]' or `(( ... ))', else the end
of the test will not be recognized.  For the for, repeat, case and
select commands no such special form for the arguments is necessary,
but the other condition (the special form of SUBLIST or use of the
SHORT_LOOPS option) still applies.


if LIST { LIST } [ elif LIST { LIST } ] ... [ else { LIST } ]
     An alternate form of if.  The rules mean that


          if [[ -o ignorebraces ]] {
            print yes
          }

     works, but


          if true {  # Does not work!
            print yes
          }

     does _not_, since the test is not suitably delimited.

if LIST SUBLIST
     A short form of the alternate `if'.  The same limitations on the
     form of LIST apply as for the previous form.

for NAME ... ( WORD ... ) SUBLIST
     A short form of for.

for NAME ... [ in WORD ... ] TERM SUBLIST
     where TERM is at least one newline or ;.  Another short form of
     for.

for (( [EXPR1] ; [EXPR2] ; [EXPR3] )) SUBLIST
     A short form of the arithmetic for command.

foreach NAME ... ( WORD ... ) LIST end
     Another form of for.

while LIST { LIST }
     An alternative form of while.  Note the limitations on the form of
     LIST mentioned above.

until LIST { LIST }
     An alternative form of until.  Note the limitations on the form of
     LIST mentioned above.

repeat WORD SUBLIST
     This is a short form of repeat.

case WORD { [ [(] PATTERN [ | PATTERN ] ... ) LIST (;;|;&|;|) ] ... }
     An alternative form of case.

select NAME [ in WORD TERM ] SUBLIST
     where TERM is at least one newline or ;.  A short form of select.


File: zsh.info,  Node: Reserved Words,  Next: Comments,  Prev: Alternate Forms For Complex Commands,  Up: Shell Grammar

6.5 Reserved Words
==================

The following words are recognized as reserved words when used as the
first word of a command unless quoted or disabled using disable -r:

do done esac then elif else fi for case if while function repeat time
until select coproc nocorrect foreach end ! [[ { }

Additionally, `}' is recognized in any position if the IGNORE_BRACES
option is not set.

File: zsh.info,  Node: Comments,  Next: Aliasing,  Prev: Reserved Words,  Up: Shell Grammar

6.6 Comments
============

In non-interactive shells, or in interactive shells with the
INTERACTIVE_COMMENTS option set, a word beginning with the third
character of the histchars parameter (`#' by default) causes that word
and all the following characters up to a newline to be ignored.

File: zsh.info,  Node: Aliasing,  Next: Quoting,  Prev: Comments,  Up: Shell Grammar

6.7 Aliasing
============

Every token in the shell input is checked to see if there is an alias
defined for it.  If so, it is replaced by the text of the alias if it
is in command position (if it could be the first word of a simple
command), or if the alias is global.  If the text ends with a space,
the next word in the shell input is treated as though it were in
command position for purposes of alias expansion.  An alias is defined
using the alias builtin; global aliases may be defined using the -g
option to that builtin.

Alias expansion is done on the shell input before any other expansion
except history expansion.  Therefore, if an alias is defined for the
word foo, alias expansion may be avoided by quoting part of the word,
e.g. \foo.  Any form of quoting works, although there is nothing to
prevent an alias being defined for the quoted form such as \foo as
well.  For use with completion, which would remove an initial backslash
followed by a character that isn't special, it may be more convenient
to quote the word by starting with a single quote, i.e. 'foo;
completion will automatically add the trailing single quote.

There is a commonly encountered problem with aliases illustrated by the
following code:


     alias echobar='echo bar'; echobar

This prints a message that the command echobar could not be found.
This happens because aliases are expanded when the code is read in; the
entire line is read in one go, so that when echobar is executed it is
too late to expand the newly defined alias.  This is often a problem in
shell scripts, functions, and code executed with `source' or `.'.
Consequently, use of functions rather than aliases is recommended in
non-interactive code.

Note also the unhelpful interaction of aliases and function definitions:


     alias func='noglob func'
     func() {
         echo Do something with $*
     }

Because aliases are expanded in function defintions, this causes the
following command to be executed:


     noglob func() {
         echo Do something with $*
     }

which defines noglob as well as func as functions with the body given.
To avoid this, either quote the name func or use the alternative
function definition form `function func'.  Ensuring the alias is
defined after the function works but is problematic if the code
fragment might be re-executed.



File: zsh.info,  Node: Quoting,  Prev: Aliasing,  Up: Shell Grammar

6.8 Quoting
===========

A character may be QUOTED (that is, made to stand for itself) by
preceding it with a `\'.  `\' followed by a newline is ignored.

A string enclosed between `$'' and `'' is processed the same way as the
string arguments of the print builtin, and the resulting string is
considered to be entirely quoted.  A literal `'' character can be
included in the string by using the `\'' escape.

All characters enclosed between a pair of single quotes ('') that is
not preceded by a `$' are quoted.  A single quote cannot appear within
single quotes unless the option RC_QUOTES is set, in which case a pair
of single quotes are turned into a single quote.  For example,


     print ''''

outputs nothing apart from a newline if RC_QUOTES is not set, but one
single quote if it is set.

Inside double quotes (""), parameter and command substitution occur,
and `\' quotes the characters `\', ``', `"', and `$'.

File: zsh.info,  Node: Redirection,  Next: Command Execution,  Prev: Shell Grammar,  Up: Top

7 Redirection
*************

If a command is followed by & and job control is not active, then the
default standard input for the command is the empty file /dev/null.
Otherwise, the environment for the execution of a command contains the
file descriptors of the invoking shell as modified by input/output
specifications.

The following may appear anywhere in a simple command or may precede or
follow a complex command.  Expansion occurs before WORD or DIGIT is
used except as noted below.  If the result of substitution on WORD
produces more than one filename, redirection occurs for each separate
filename in turn.


< WORD
     Open file WORD for reading as standard input.

<> WORD
     Open file WORD for reading and writing as standard input.  If the
     file does not exist then it is created.

> WORD
     Open file WORD for writing as standard output.  If the file does
     not exist then it is created.  If the file exists, and the CLOBBER
     option is unset, this causes an error; otherwise, it is truncated
     to zero length.

>| WORD
>! WORD
     Same as >, except that the file is truncated to zero length if it
     exists, even if CLOBBER is unset.

>> WORD
     Open file WORD for writing in append mode as standard output.  If
     the file does not exist, and the CLOBBER option is unset, this
     causes an error; otherwise, the file is created.

>>| WORD
>>! WORD
     Same as >>, except that the file is created if it does not exist,
     even if CLOBBER is unset.

<<[-] WORD
     The shell input is read up to a line that is the same as WORD, or
     to an end-of-file.  No parameter expansion, command substitution or
     filename generation is performed on WORD.  The resulting document,
     called a _here-document_, becomes the standard input.

     If any character of WORD is quoted with single or double quotes or
     a `\', no interpretation is placed upon the characters of the
     document.  Otherwise, parameter and command substitution occurs,
     `\' followed by a newline is removed, and `\' must be used to
     quote the characters `\', `$', ``' and the first character of WORD.

     Note that WORD itself does not undergo shell expansion.  Backquotes
     in WORD do not have their usual effect; instead they behave
     similarly to double quotes, except that the backquotes themselves
     are passed through unchanged.  (This information is given for
     completeness and it is not recommended that backquotes be used.)
     Quotes in the form $'...' have their standard effect of expanding
     backslashed references to special characters.

     If <<- is used, then all leading tabs are stripped from WORD and
     from the document.

<<< WORD
     Perform shell expansion on WORD and pass the result to standard
     input.  This is known as a _here-string_.  Compare the use of WORD
     in here-documents above, where WORD does not undergo shell
     expansion.

<& NUMBER
>& NUMBER
     The standard input/output is duplicated from file descriptor
     NUMBER (see man page dup2(2)).

<& -
>& -
     Close the standard input/output.

<& p
>& p
     The input/output from/to the coprocess is moved to the standard
     input/output.

>& WORD
&> WORD
     (Except where `>& WORD' matches one of the above syntaxes; `&>'
     can always be used to avoid this ambiguity.)  Redirects both
     standard output and standard error (file descriptor 2) in the
     manner of `> WORD'.  Note that this does _not_ have the same
     effect as `> WORD 2>&1' in the presence of multios (see the
     section below).

>&| WORD
>&! WORD
&>| WORD
&>! WORD
     Redirects both standard output and standard error (file descriptor
     2) in the manner of `>| WORD'.

>>& WORD
&>> WORD
     Redirects both standard output and standard error (file descriptor
     2) in the manner of `>> WORD'.

>>&| WORD
>>&! WORD
&>>| WORD
&>>! WORD
     Redirects both standard output and standard error (file descriptor
     2) in the manner of `>>| WORD'.


If one of the above is preceded by a digit, then the file descriptor
referred to is that specified by the digit instead of the default 0 or
1.  The order in which redirections are specified is significant.  The
shell evaluates each redirection in terms of the (_file descriptor_,
_file_) association at the time of evaluation.  For example:



     ... 1>FNAME 2>&1

first associates file descriptor 1 with file FNAME.  It then associates
file descriptor 2 with the file associated with file descriptor 1 (that
is, FNAME).  If the order of redirections were reversed, file
descriptor 2 would be associated with the terminal (assuming file
descriptor 1 had been) and then file descriptor 1 would be associated
with file FNAME.

If instead of a digit one of the operators above is preceded by a valid
identifier enclosed in braces, the shell will open a new file
descriptor that is guaranteed to be at least 10 and set the parameter
named by the identifier to the file descriptor opened.  No whitespace
is allowed between the closing brace and the redirection character.
The option IGNORE_BRACES must not be set.  For example:



     ... {myfd}>&1

This opens a new file descriptor that is a duplicate of file descriptor
1 and sets the parameter myfd to the number of the file descriptor,
which will be at least 10.  The new file descriptor can be written to
using the syntax >&$myfd.

The syntax {VARID}>&-, for example {myfd}>&-, may be used to close a
file descriptor opened in this fashion.  Note that the parameter given
by VARID must previously be set to a file descriptor in this case.

It is an error to open or close a file descriptor in this fashion when
the parameter is readonly.  However, it is not an error to read or
write a file descriptor using <&$PARAM or >&$PARAM if PARAM is readonly.

If the option CLOBBER is unset, it is an error to open a file
descriptor using a parameter that is already set to an open file
descriptor previously allocated by this mechanism.  Unsetting the
parameter before using it for allocating a file descriptor avoids the
error.

Note that this mechanism merely allocates or closes a file descriptor;
it does not perform any redirections from or to it.  It is usually
convenient to allocate a file descriptor prior to use as an argument to
exec.  The following shows a typical sequence of allocation, use, and
closing of a file descriptor:


     integer myfd
     exec {myfd}>~/logs/mylogfile.txt
     print This is a log message. >&$myfd
     exec {myfd}>&-

Note that the expansion of the variable in the expression >&$myfd
occurs at the point the redirection is opened.  This is after the
expansion of command arguments and after any redirections to the left
on the command line have been processed.

The `|&' command separator described in *note Simple Commands &
Pipelines:: is a shorthand for `2>&1 |'.

The various forms of process substitution, `<(LIST)', and `=(LIST())'
for input and `>(LIST)' for output, are often used together with
redirection.  For example, if WORD in an output redirection is of the
form `>(LIST)' then the output is piped to the command represented by
LIST.  See *note Process Substitution::.

7.1 Multios
===========

If the user tries to open a file descriptor for writing more than once,
the shell opens the file descriptor as a pipe to a process that copies
its input to all the specified outputs, similar to `tee', provided the
MULTIOS option is set, as it is by default.  Thus:


     date >foo >bar

writes the date to two files, named `foo' and `bar'.  Note that a pipe
is an implicit redirection; thus


     date >foo | cat

writes the date to the file `foo', and also pipes it to cat.

If the MULTIOS option is set, the word after a redirection operator is
also subjected to filename generation (globbing).  Thus


     : > *

will truncate all files in the current directory, assuming there's at
least one.  (Without the MULTIOS option, it would create an empty file
called `*'.)  Similarly, you can do


     echo exit 0 >> *.sh

If the user tries to open a file descriptor for reading more than once,
the shell opens the file descriptor as a pipe to a process that copies
all the specified inputs to its output in the order specified, similar
to `cat', provided the MULTIOS option is set.  Thus


     sort <foo <fubar

or even


     sort <f{oo,ubar}

is equivalent to `cat foo fubar | sort'.

Expansion of the redirection argument occurs at the point the
redirection is opened, at the point described above for the expansion
of the variable in >&$myfd.

Note that a pipe is an implicit redirection; thus


     cat bar | sort <foo

is equivalent to `cat bar foo | sort' (note the order of the inputs).

If the MULTIOS option is _un_set, each redirection replaces the
previous redirection for that file descriptor.  However, all files
redirected to are actually opened, so


     echo foo > bar > baz

when MULTIOS is unset will truncate bar, and write `foo' into baz.

There is a problem when an output multio is attached to an external
program.  A simple example shows this:


     cat file >file1 >file2
     cat file1 file2

Here, it is possible that the second `cat' will not display the full
contents of file1 and file2 (i.e. the original contents of file
repeated twice).

The reason for this is that the multios are spawned after the cat
process is forked from the parent shell, so the parent shell does not
wait for the multios to finish writing data.  This means the command as
shown can exit before file1 and file2 are completely written.  As a
workaround, it is possible to run the cat process as part of a job in
the current shell:


     { cat file } >file >file2

Here, the {...} job will pause to wait for both files to be written.



7.2 Redirections with no command
================================

When a simple command consists of one or more redirection operators and
zero or more parameter assignments, but no command name, zsh can behave
in several ways.

If the parameter NULLCMD is not set or the option CSH_NULLCMD is set,
an error is caused.  This is the `csh' behavior and CSH_NULLCMD is set
by default when emulating `csh'.

If the option SH_NULLCMD is set, the builtin `:' is inserted as a
command with the given redirections.  This is the default when emulating
`sh' or `ksh'.

Otherwise, if the parameter NULLCMD is set, its value will be used as a
command with the given redirections.  If both NULLCMD and READNULLCMD
are set, then the value of the latter will be used instead of that of
the former when the redirection is an input.  The default for NULLCMD
is `cat' and for READNULLCMD is `more'. Thus


     < file

shows the contents of file on standard output, with paging if that is a
terminal.  NULLCMD and READNULLCMD may refer to shell functions.



File: zsh.info,  Node: Command Execution,  Next: Functions,  Prev: Redirection,  Up: Top

8 Command Execution
*******************

If a command name contains no slashes, the shell attempts to locate it.
If there exists a shell function by that name, the function is invoked
as described in *note Functions::.  If there exists a shell builtin by
that name, the builtin is invoked.

Otherwise, the shell searches each element of $path for a directory
containing an executable file by that name.  If the search is
unsuccessful, the shell prints an error message and returns a nonzero
exit status.

If execution fails because the file is not in executable format, and
the file is not a directory, it is assumed to be a shell script.
/bin/sh is spawned to execute it.  If the program is a file beginning
with `#!', the remainder of the first line specifies an interpreter for
the program.  The shell will execute the specified interpreter on
operating systems that do not handle this executable format in the
kernel.

If no external command is found but a function command_not_found_handler
exists the shell executes this function with all command line
arguments.  The function should return status zero if it successfully
handled the command, or non-zero status if it failed.  In the latter
case the standard handling is applied: `command not found' is printed
to standard error and the shell exits with status 127.  Note that the
handler is executed in a subshell forked to execute an external
command, hence changes to directories, shell parameters, etc. have no
effect on the main shell.

File: zsh.info,  Node: Functions,  Next: Jobs & Signals,  Prev: Command Execution,  Up: Top

9 Functions
***********

Shell functions are defined with the function reserved word or the
special syntax `FUNCNAME ()'.  Shell functions are read in and stored
internally.  Alias names are resolved when the function is read.
Functions are executed like commands with the arguments passed as
positional parameters.  (See *note Command Execution::.)

Functions execute in the same process as the caller and share all files
and present working directory with the caller.  A trap on EXIT set
inside a function is executed after the function completes in the
environment of the caller.

The return builtin is used to return from function calls.

Function identifiers can be listed with the functions builtin.  Functions
can be undefined with the unfunction builtin.

9.1 Autoloading Functions
=========================



A function can be marked as _undefined_ using the autoload builtin (or
`functions -u' or `typeset -fu').  Such a function has no body.  When
the function is first executed, the shell searches for its definition
using the elements of the fpath variable.  Thus to define functions for
autoloading, a typical sequence is:


     fpath=(~/myfuncs $fpath)
     autoload myfunc1 myfunc2 ...

The usual alias expansion during reading will be suppressed if the
autoload builtin or its equivalent is given the option -U. This is
recommended for the use of functions supplied with the zsh distribution.  Note
that for functions precompiled with the zcompile builtin command the
flag -U must be provided when the .zwc file is created, as the
corresponding information is compiled into the latter.

For each ELEMENT in fpath, the shell looks for three possible files,
the newest of which is used to load the definition for the function:


ELEMENT.zwc
     A file created with the zcompile builtin command, which is
     expected to contain the definitions for all functions in the
     directory named ELEMENT.  The file is treated in the same manner
     as a directory containing files for functions and is searched for
     the definition of the function.   If the definition is not found,
     the search for a definition proceeds with the other two
     possibilities described below.

     If ELEMENT already includes a .zwc extension (i.e. the extension
     was explicitly given by the user), ELEMENT is searched for the
     definition of the function without comparing its age to that of
     other files; in fact, there does not need to be any directory
     named ELEMENT without the suffix.  Thus including an element such
     as `/usr/local/funcs.zwc' in fpath will speed up the search for
     functions, with the disadvantage that functions included must be
     explicitly recompiled by hand before the shell notices any changes.

ELEMENT/FUNCTION.zwc
     A file created with zcompile, which is expected to contain the
     definition for FUNCTION.  It may include other function definitions
     as well, but those are neither loaded nor executed; a file found
     in this way is searched _only_ for the definition of FUNCTION.

ELEMENT/FUNCTION
     A file of zsh command text, taken to be the definition for
     FUNCTION.


In summary, the order of searching is, first, in the _parents of_
directories in fpath for the newer of either a compiled directory or a
directory in fpath; second, if more than one of these contains a
definition for the function that is sought, the leftmost in the fpath
is chosen; and third, within a directory, the newer of either a compiled
function or an ordinary function definition is used.

If the KSH_AUTOLOAD option is set, or the file contains only a simple
definition of the function, the file's contents will be executed.  This
will normally define the function in question, but may also perform
initialization, which is executed in the context of the function
execution, and may therefore define local parameters.  It is an error
if the function is not defined by loading the file.

Otherwise, the function body (with no surrounding `FUNCNAME() {...}')
is taken to be the complete contents of the file.  This form allows the
file to be used directly as an executable shell script.  If processing
of the file results in the function being re-defined, the function
itself is not re-executed.  To force the shell to perform
initialization and then call the function defined, the file should
contain initialization code (which will be executed then discarded) in
addition to a complete function definition (which will be retained for
subsequent calls to the function), and a call to the shell function,
including any arguments, at the end.

For example, suppose the autoload file func contains


     func() { print This is func; }
     print func is initialized

then `func; func' with KSH_AUTOLOAD set will produce both messages on
the first call, but only the message `This is func' on the second and
subsequent calls.  Without KSH_AUTOLOAD set, it will produce the
initialization message on the first call, and the other message on the
second and subsequent calls.

It is also possible to create a function that is not marked as
autoloaded, but which loads its own definition by searching fpath, by
using `autoload -X' within a shell function.  For example, the
following are equivalent:


     myfunc() {
       autoload -X
     }
     myfunc args...

and


     unfunction myfunc   # if myfunc was defined
     autoload myfunc
     myfunc args...

In fact, the functions command outputs `builtin autoload -X' as the
body of an autoloaded function.  This is done so that


     eval "$(functions)"

produces a reasonable result.  A true autoloaded function can be
identified by the presence of the comment `# undefined' in the body,
because all comments are discarded from defined functions.

To load the definition of an autoloaded function myfunc without
executing myfunc, use:


     autoload +X myfunc


9.2 Anonymous Functions
=======================



If no name is given for a function, it is `anonymous' and is handled
specially.  Either form of function definition may be used: a `()' with
no preceding name, or a `function' with an immediately following open
brace.  The function is executed immediately at the point of definition
and is not stored for future use.  The function name is set to `(anon)'
and the parameter list passed to the function is empty.  Note that this
means the argument list of any enclosing script or function is hidden.
Redirections may be applied to the anonymous function in the same
manner as to a current-shell structure enclosed in braces.  The main
use of anonymous functions is to provide a scope for local variables.
This is particularly convenient in start-up files as these do not
provide their own local variable scope.

For example,


     variable=outside
     function {
       local variable=inside
       print "I am $variable"
     }
     print "I am $variable"

outputs the following:


     I am inside
     I am outside

Note that function definitions with arguments that expand to nothing,
for example `name=; function $name { ... }', are not treated as
anonymous functions.  Instead, they are treated as normal function
definitions where the definition is silently discarded.



9.3 Special Functions
=====================

Certain functions, if defined, have special meaning to the shell.



9.3.1 Hook Functions
--------------------



For the functions below, it is possible to define an array that has the
same name as the function with `_functions' appended.  Any element in
such an array is taken as the name of a function to execute; it is
executed in the same context and with the same arguments as the basic
function.  For example, if $chpwd_functions is an array containing the
values `mychpwd', `chpwd_save_dirstack', then the shell attempts to
execute the functions `chpwd', `mychpwd' and `chpwd_save_dirstack', in
that order.  Any function that does not exist is silently ignored.  A
function found by this mechanism is referred to elsewhere as a `hook
function'.  An error in any function causes subsequent functions not to
be run.  Note further that an error in a precmd hook causes an
immediately following periodic function not to run (though it may run
at the next opportunity).


chpwd
     Executed whenever the current working directory is changed.

periodic
     If the parameter PERIOD is set, this function is executed every
     $PERIOD seconds, just before a prompt.  Note that if multiple
     functions are defined using the array periodic_functions only one
     period is applied to the complete set of functions, and the
     scheduled time is not reset if the list of functions is altered.
     Hence the set of functions is always called together.

precmd
     Executed before each prompt.  Note that precommand functions are
     not re-executed simply because the command line is redrawn, as
     happens, for example, when a notification about an exiting job is
     displayed.

preexec
     Executed just after a command has been read and is about to be
     executed.  If the history mechanism is active (and the line was not
     discarded from the history buffer), the string that the user typed
     is passed as the first argument, otherwise it is an empty string.
     The actual command that will be executed (including expanded
     aliases) is passed in two different forms: the second argument is
     a single-line, size-limited version of the command (with things
     like function bodies elided); the third argument contains the full
     text that is being executed.

zshaddhistory
     Executed when a history line has been read interactively, but
     before it is executed.  The sole argument is the complete history
     line (so that any terminating newline will still be present).

     If any of the hook functions return a non-zero value the history
     line will not be saved, although it lingers in the history until
     the next line is executed allow you to reuse or edit it
     immediately.

     A hook function may call `fc -p ...' to switch the history context
     so that the history is saved in a different file from the that in
     the global HISTFILE parameter.  This is handled specially: the
     history context is automatically restored after the processing of
     the history line is finished.

     The following example function first adds the history line to the
     normal history with the newline stripped,  which is usually the
     correct behaviour.  Then it switches the history context so that
     the line will be written to a history file in the current
     directory.


          zshaddhistory() {
            print -sr -- ${1%%$'\n'}
            fc -p .zsh_local_history
          }

zshexit
     Executed at the point where the main shell is about to exit
     normally.  This is not called by exiting subshells, nor when the
     exec precommand modifier is used before an external command.
     Also, unlike TRAPEXIT, it is not called when functions exit.



9.3.2 Trap Functions
--------------------

The functions below are treated specially but do not have corresponding
hook arrays.


TRAPNAL
     If defined and non-null, this function will be executed whenever
     the shell catches a signal SIGNAL, where NAL is a signal name as
     specified for the kill builtin.  The signal number will be passed
     as the first parameter to the function.

     If a function of this form is defined and null, the shell and
     processes spawned by it will ignore SIGNAL.

     The return status from the function is handled specially.  If it is
     zero, the signal is assumed to have been handled, and execution
     continues normally.  Otherwise, the shell will behave as
     interrupted except that the return status of the trap is retained.

     Programs terminated by uncaught signals typically return the
     status 128 plus the signal number.  Hence the following causes the
     handler for SIGINT to print a message, then mimic the usual effect
     of the signal.


          TRAPINT() {
            print "Caught SIGINT, aborting."
            return $(( 128 + $1 ))
          }

     The functions TRAPZERR, TRAPDEBUG and TRAPEXIT are never executed
     inside other traps.

TRAPDEBUG
     If the option DEBUG_BEFORE_CMD is set (as it is by default),
     executed before each command; otherwise executed after each
     command.  See the description of the trap builtin in *note Shell
     Builtin Commands:: for details of additional features provided in
     debug traps.

TRAPEXIT
     Executed when the shell exits, or when the current function exits
     if defined inside a function.  The value of $? at the start of
     execution is the exit status of the shell or the return status of
     the function exiting.

TRAPZERR
     Executed whenever a command has a non-zero exit status.  However,
     the function is not executed if the command occurred in a sublist
     followed by `&&' or `||'; only the final command in a sublist of
     this type causes the trap to be executed.  The function TRAPERR
     acts the same as TRAPZERR on systems where there is no SIGERR
     (this is the usual case).


The functions beginning `TRAP' may alternatively be defined with the
trap builtin:  this may be preferable for some uses, as they are then
run in the environment of the calling process, rather than in their own
function environment.  Apart from the difference in calling procedure
and the fact that the function form appears in lists of functions, the
forms


     TRAPNAL() {
      # code
     }

and


     trap '
      # code
     ' NAL

are equivalent.

File: zsh.info,  Node: Jobs & Signals,  Next: Arithmetic Evaluation,  Prev: Functions,  Up: Top

10 Jobs & Signals
*****************



10.1 Jobs
=========

If the MONITOR option is set, an interactive shell associates a _job_
with each pipeline.  It keeps a table of current jobs, printed by the
jobs command, and assigns them small integer numbers.  When a job is
started asynchronously with `&', the shell prints a line to standard
error which looks like:


     [1] 1234

indicating that the job which was started asynchronously was job number
1 and had one (top-level) process, whose process ID was 1234.

If a job is started with `&|' or `&!', then that job is immediately
disowned.  After startup, it does not have a place in the job table,
and is not subject to the job control features described here.

If you are running a job and wish to do something else you may hit the
key ^Z (control-Z) which sends a TSTP signal to the current job:  this
key may be redefined by the susp option of the external stty command.  The
shell will then normally indicate that the job has been `suspended',
and print another prompt.  You can then manipulate the state of this
job, putting it in the background with the bg command, or run some other
commands and then eventually bring the job back into the foreground with the
foreground command fg.  A ^Z takes effect immediately and is like an
interrupt in that pending output and unread input are discarded when it
is typed.

A job being run in the background will suspend if it tries to read from
the terminal.  Background jobs are normally allowed to produce output,
but this can be disabled by giving the command `stty tostop'.  If you
set this tty option, then background jobs will suspend when they try to
produce output like they do when they try to read input.

When a command is suspended and continued later with the fg or wait
builtins, zsh restores tty modes that were in effect when it was
suspended.  This (intentionally) does not apply if the command is
continued via `kill -CONT', nor when it is continued with bg.

There are several ways to refer to jobs in the shell.  A job can be
referred to by the process ID of any process of the job or by one of
the following:


%NUMBER
     The job with the given number.

%STRING
     Any job whose command line begins with STRING.

%?STRING
     Any job whose command line contains STRING.

%%
     Current job.

%+
     Equivalent to `%%'.

%-
     Previous job.

The shell learns immediately whenever a process changes state.  It
normally informs you whenever a job becomes blocked so that no further
progress is possible.  If the NOTIFY option is not set, it waits until
just before it prints a prompt before it informs you.  All such
notifications are sent directly to the terminal, not to the standard
output or standard error.

When the monitor mode is on, each background job that completes
triggers any trap set for CHLD.

When you try to leave the shell while jobs are running or suspended,
you will be warned that `You have suspended (running) jobs'.  You may
use the jobs command to see what they are.  If you do this or
immediately try to exit again, the shell will not warn you a second
time; the suspended jobs will be terminated, and the running jobs will
be sent a SIGHUP signal, if the HUP option is set.

To avoid having the shell terminate the running jobs, either use the
`nohup' command (see man page nohup(1)) or the disown builtin.

10.2 Signals
============

The INT and QUIT signals for an invoked command are ignored if the
command is followed by `&' and the MONITOR option is not active.  The
shell itself always ignores the QUIT signal.  Otherwise, signals have
the values inherited by the shell from its parent (but see the TRAPNAL
special functions in *note Functions::).

File: zsh.info,  Node: Arithmetic Evaluation,  Next: Conditional Expressions,  Prev: Jobs & Signals,  Up: Top

11 Arithmetic Evaluation
************************

The shell can perform integer and floating point arithmetic, either
using the builtin let, or via a substitution of the form $((...)).  For
integers, the shell is usually compiled to use 8-byte precision where
this is available, otherwise precision is 4 bytes.  This can be tested,
for example, by giving the command `print - $(( 12345678901 ))'; if the
number appears unchanged, the precision is at least 8 bytes.  Floating
point arithmetic always uses the `double' type with whatever
corresponding precision is provided by the compiler and the library.

The let builtin command takes arithmetic expressions as arguments; each
is evaluated separately.  Since many of the arithmetic operators, as
well as spaces, require quoting, an alternative form is provided: for
any command which begins with a `((', all the characters until a
matching `))' are treated as a quoted expression and arithmetic
expansion performed as for an argument of let.  More precisely,
`((...))' is equivalent to `let "..."'.  The return status is 0 if the
arithmetic value of the expression is non-zero, 1 if it is zero, and 2
if an error occurred.

For example, the following statement


     (( val = 2 + 1 ))

is equivalent to


     let "val = 2 + 1"

both assigning the value 3 to the shell variable val and returning a
zero status.

Integers can be in bases other than 10.  A leading `0x' or `0X' denotes
hexadecimal.  Integers may also be of the form `BASE#N', where BASE is
a decimal number between two and thirty-six representing the arithmetic
base and N is a number in that base (for example, `16#ff' is 255 in
hexadecimal).  The BASE# may also be omitted, in which case base 10 is
used.  For backwards compatibility the form `[BASE]N' is also accepted.

It is also possible to specify a base to be used for output in the form
`[#BASE]', for example `[#16]'.  This is used when outputting
arithmetical substitutions or when assigning to scalar parameters, but
an explicitly defined integer or floating point parameter will not be
affected.  If an integer variable is implicitly defined by an
arithmetic expression, any base specified in this way will be set as the
variable's output arithmetic base as if the option `-i BASE' to the
typeset builtin had been used.  The expression has no precedence and if
it occurs more than once in a mathematical expression, the last
encountered is used.  For clarity it is recommended that it appear at
the beginning of an expression.  As an example:


     typeset -i 16 y
     print $(( [#8] x = 32, y = 32 ))
     print $x $y

outputs first `8#40', the rightmost value in the given output base, and
then `8#40 16#20', because y has been explicitly declared to have
output base 16, while x (assuming it does not already exist) is
implicitly typed by the arithmetic evaluation, where it acquires the
output base 8.

If the C_BASES option is set, hexadecimal numbers in the standard C
format, for example 0xFF instead of the usual `16#FF'.  If the option
OCTAL_ZEROES is also set (it is not by default), octal numbers will be
treated similarly and hence appear as `077' instead of `8#77'.  This
option has no effect on the output of bases other than hexadecimal and
octal, and these formats are always understood on input.

When an output base is specified using the `[#BASE]' syntax, an
appropriate base prefix will be output if necessary, so that the value
output is valid syntax for input.  If the # is doubled, for example
`[##16]', then no base prefix is output.

Floating point constants are recognized by the presence of a decimal
point or an exponent.  The decimal point may be the first character of
the constant, but the exponent character e or E may not, as it will be
taken for a parameter name.

An arithmetic expression uses nearly the same syntax and associativity
of expressions as in C.

In the native mode of operation, the following operators are supported
(listed in decreasing order of precedence):


+ - ! ~ ++ -
     unary plus/minus, logical NOT, complement, {pre,post}{in,de}crement

<< >>
     bitwise shift left, right

&
     bitwise AND

^
     bitwise XOR

|
     bitwise OR

**
     exponentiation

* / %
     multiplication, division, modulus (remainder)

+ -
     addition, subtraction

< > <= >=
     comparison

== !=
     equality and inequality

&&
     logical AND

|| ^^
     logical OR, XOR

? :
     ternary operator

= += -= *= /= %= &= ^= |= <<= >>= &&= ||= ^^= **=
     assignment

,
     comma operator

The operators `&&', `||', `&&=', and `||=' are short-circuiting, and
only one of the latter two expressions in a ternary operator is
evaluated.  Note the precedence of the bitwise AND, OR, and XOR
operators.

With the option C_PRECEDENCES the precedences (but no other properties)
of the operators are altered to be the same as those in most other
languages that support the relevant operators:


+ - ! ~ ++ -
     unary plus/minus, logical NOT, complement, {pre,post}{in,de}crement

**
     exponentiation

* / %
     multiplication, division, modulus (remainder)

+ -
     addition, subtraction

<< >>
     bitwise shift left, right

< > <= >=
     comparison

== !=
     equality and inequality

&
     bitwise AND

^
     bitwise XOR

|
     bitwise OR

&&
     logical AND

^^
     logical XOR

||
     logical OR

? :
     ternary operator

= += -= *= /= %= &= ^= |= <<= >>= &&= ||= ^^= **=
     assignment

,
     comma operator

Note the precedence of exponentiation in both cases is below that of
unary operators, hence `-3**2' evaluates as `9', not -9.  Use
parentheses where necessary: `-(3**2)'.  This is for compatibility with
other shells.

Mathematical functions can be called with the syntax `FUNC(ARGS)',
where the function decides if the ARGS is used as a string or a
comma-separated list of arithmetic expressions. The shell currently
defines no mathematical functions by default, but the module
zsh/mathfunc may be loaded with the zmodload builtin to provide
standard floating point mathematical functions.

An expression of the form `##X' where X is any character sequence such
as `a', `^A', or `\M-\C-x' gives the value of this character and an
expression of the form `#FOO' gives the value of the first character of
the contents of the parameter FOO.  Character values are according to
the character set used in the current locale; for multibyte character
handling the option MULTIBYTE must be set.  Note that this form is
different from `$#FOO', a standard parameter substitution which gives
the length of the parameter FOO.  `#\' is accepted instead of `##', but
its use is deprecated.

Named parameters and subscripted arrays can be referenced by name
within an arithmetic expression without using the parameter expansion
syntax.  For example,


     ((val2 = val1 * 2))

assigns twice the value of $val1 to the parameter named val2.

An internal integer representation of a named parameter can be
specified with the integer builtin.  Arithmetic evaluation is performed
on the value of each assignment to a named parameter declared integer
in this manner.  Assigning a floating point number to an integer
results in rounding down to the next integer.

Likewise, floating point numbers can be declared with the float
builtin; there are two types, differing only in their output format, as
described for the typeset builtin.  The output format can be bypassed
by using arithmetic substitution instead of the parameter substitution,
i.e. `${FLOAT}' uses the defined format, but `$((FLOAT))' uses a
generic floating point format.

Promotion of integer to floating point values is performed where
necessary.  In addition, if any operator which requires an integer
(`~', `&', `|', `^', `%', `<<', `>>' and their equivalents with
assignment) is given a floating point argument, it will be silently
rounded down to the next integer.

Scalar variables can hold integer or floating point values at different
times; there is no memory of the numeric type in this case.

If a variable is first assigned in a numeric context without previously
being declared, it will be implicitly typed as integer or float and
retain that type either until the type is explicitly changed or until
the end of the scope.  This can have unforeseen consequences.  For
example, in the loop


     for (( f = 0; f < 1; f += 0.1 )); do
     # use $f
     done

if f has not already been declared, the first assignment will cause it
to be created as an integer, and consequently the operation `f += 0.1'
will always cause the result to be truncated to zero, so that the loop
will fail.  A simple fix would be to turn the initialization into `f =
0.0'.  It is therefore best to declare numeric variables with explicit
types.

File: zsh.info,  Node: Conditional Expressions,  Next: Prompt Expansion,  Prev: Arithmetic Evaluation,  Up: Top

12 Conditional Expressions
**************************

A _conditional expression_ is used with the [[ compound command to test
attributes of files and to compare strings.  Each expression can be
constructed from one or more of the following unary or binary
expressions:


-a FILE
     true if FILE exists.

-b FILE
     true if FILE exists and is a block special file.

-c FILE
     true if FILE exists and is a character special file.

-d FILE
     true if FILE exists and is a directory.

-e FILE
     true if FILE exists.

-f FILE
     true if FILE exists and is a regular file.

-g FILE
     true if FILE exists and has its setgid bit set.

-h FILE
     true if FILE exists and is a symbolic link.

-k FILE
     true if FILE exists and has its sticky bit set.

-n STRING
     true if length of STRING is non-zero.

-o OPTION
     true if option named OPTION is on.  OPTION may be a single
     character, in which case it is a single letter option name.  (See
     *note Specifying Options::.)

-p FILE
     true if FILE exists and is a FIFO special file (named pipe).

-r FILE
     true if FILE exists and is readable by current process.

-s FILE
     true if FILE exists and has size greater than zero.

-t FD
     true if file descriptor number FD is open and associated with a
     terminal device.  (note: FD is not optional)

-u FILE
     true if FILE exists and has its setuid bit set.

-w FILE
     true if FILE exists and is writable by current process.

-x FILE
     true if FILE exists and is executable by current process.  If FILE
     exists and is a directory, then the current process has permission
     to search in the directory.

-z STRING
     true if length of STRING is zero.

-L FILE
     true if FILE exists and is a symbolic link.

-O FILE
     true if FILE exists and is owned by the effective user ID of this
     process.

-G FILE
     true if FILE exists and its group matches the effective group ID
     of this process.

-S FILE
     true if FILE exists and is a socket.

-N FILE
     true if FILE exists and its access time is not newer than its
     modification time.

FILE1 -nt FILE2
     true if FILE1 exists and is newer than FILE2.

FILE1 -ot FILE2
     true if FILE1 exists and is older than FILE2.

FILE1 -ef FILE2
     true if FILE1 and FILE2 exist and refer to the same file.

STRING = PATTERN
STRING == PATTERN
     true if STRING matches PATTERN.  The `==' form is the preferred
     one.  The `=' form is for backward compatibility and should be
     considered obsolete.

STRING != PATTERN
     true if STRING does not match PATTERN.

STRING =~ REGEXP
     true if STRING matches the regular expression REGEXP.  If the
     option RE_MATCH_PCRE is set REGEXP is tested as a PCRE regular
     expression using the zsh/pcre module, else it is tested as a POSIX
     extended regular expression using the zsh/regex module.  Upon
     successful match, some variables will be updated; no variables are
     changed if the matching fails.

     If the option BASH_REMATCH is not set the scalar parameter MATCH
     is set to the substring that matched the pattern and the integer
     parameters MBEGIN and MEND to the index of the start and end,
     respectively, of the match in STRING, such that if STRING is
     contained in variable var the expression `${var[$MBEGIN,$MEND]}'
     is identical to `$MATCH'.  The setting of the option KSH_ARRAYS is
     respected.  Likewise, the array match is set to the substrings
     that matched parenthesised subexpressions and the arrays mbegin
     and mend to the indices of the start and end positions,
     respectively, of the substrings within STRING.  The arrays are not
     set if there were no parenthesised subexpresssions.  For example,
     if the string `a short string' is matched against the regular
     expression `s(...)t', then (assuming the option KSH_ARRAYS is not
     set) MATCH, MBEGIN and MEND are `short', 3 and 7, respectively,
     while match, mbegin and mend are single entry arrays containing
     the strings `hor', `4' and `6, respectively.

     If the option BASH_REMATCH is set the array BASH_REMATCH is set to
     the substring that matched the pattern followed by the substrings
     that matched parenthesised subexpressions within the pattern.

STRING1 < STRING2
     true if STRING1 comes before STRING2 based on ASCII value of their
     characters.

STRING1 > STRING2
     true if STRING1 comes after STRING2 based on ASCII value of their
     characters.

EXP1 -eq EXP2
     true if EXP1 is numerically equal to EXP2.

EXP1 -ne EXP2
     true if EXP1 is numerically not equal to EXP2.

EXP1 -lt EXP2
     true if EXP1 is numerically less than EXP2.

EXP1 -gt EXP2
     true if EXP1 is numerically greater than EXP2.

EXP1 -le EXP2
     true if EXP1 is numerically less than or equal to EXP2.

EXP1 -ge EXP2
     true if EXP1 is numerically greater than or equal to EXP2.

( EXP )
     true if EXP is true.

! EXP
     true if EXP is false.

EXP1 && EXP2
     true if EXP1 and EXP2 are both true.

EXP1 || EXP2
     true if either EXP1 or EXP2 is true.


Normal shell expansion is performed on the FILE, STRING and PATTERN
arguments, but the result of each expansion is constrained to be a
single word, similar to the effect of double quotes.  File generation
is not performed on any form of argument to conditions.  However,
pattern metacharacters are active for the PATTERN arguments; the
patterns are the same as those used for filename generation, see *note
Filename Generation::, but there is no special behaviour of `/' nor
initial dots, and no glob qualifiers are allowed.

In each of the above expressions, if FILE is of the form `/dev/fd/N',
where N is an integer, then the test applied to the open file whose
descriptor number is N, even if the underlying system does not support
the /dev/fd directory.

In the forms which do numeric comparison, the expressions EXP undergo
arithmetic expansion as if they were enclosed in $((...)).

For example, the following:


     [[ ( -f foo || -f bar ) && $report = y* ]] && print File exists.

tests if either file foo or file bar exists, and if so, if the value of
the parameter report begins with `y'; if the complete condition is
true, the message `File exists.' is printed.

File: zsh.info,  Node: Prompt Expansion,  Next: Expansion,  Prev: Conditional Expressions,  Up: Top

13 Prompt Expansion
*******************



13.1 Expansion of Prompt Sequences
==================================

Prompt sequences undergo a special form of expansion.  This type of
expansion is also available using the -P option to the print builtin.

If the PROMPT_SUBST option is set, the prompt string is first subjected
to _parameter expansion_, _command substitution_ and _arithmetic
expansion_.  See *note Expansion::.

Certain escape sequences may be recognised in the prompt string.

If the PROMPT_BANG option is set, a `!' in the prompt is replaced by
the current history event number.  A literal `!' may then be
represented as `!!'.

If the PROMPT_PERCENT option is set, certain escape sequences that
start with `%' are expanded.  Many escapes are followed by a single
character, although some of these take an optional integer argument that
should appear between the `%' and the next character of the sequence.
More complicated escape sequences are available to provide conditional
expansion.



13.2 Simple Prompt Escapes
==========================



13.2.1 Special characters
-------------------------


%%
     A `%'.

%)
     A `)'.



13.2.2 Login information
------------------------


%l
     The line (tty) the user is logged in on, without `/dev/' prefix.
     If the name starts with `/dev/tty', that prefix is stripped.

%M
     The full machine hostname.

%m
     The hostname up to the first `.'.  An integer may follow the `%'
     to specify how many components of the hostname are desired.  With
     a negative integer, trailing components of the hostname are shown.

%n
     $USERNAME.

%y
     The line (tty) the user is logged in on, without `/dev/' prefix.
     This does not treat `/dev/tty' names specially.



13.2.3 Shell state
------------------


%#
     A `#' if the shell is running with privileges, a `%' if not.
     Equivalent to `%(!.#.%%)'.  The definition of `privileged', for
     these purposes, is that either the effective user ID is zero, or,
     if POSIX.1e capabilities are supported, that at least one
     capability is raised in either the Effective or Inheritable
     capability vectors.

%?
     The return status of the last command executed just before the
     prompt.

%_
     The status of the parser, i.e. the shell constructs (like `if' and
     `for') that have been started on the command line. If given an
     integer number that many strings will be printed; zero or negative
     or no integer means print as many as there are.  This is most
     useful in prompts PS2 for continuation lines and PS4 for debugging
     with the XTRACE option; in the latter case it will also work
     non-interactively.

%d
/
     Current working directory.  If an integer follows the `%', it
     specifies a number of trailing components of the current working
     directory to show; zero means the whole path.  A negative integer
     specifies leading components, i.e. %-1d specifies the first
     component.

%~
     As %d and %/, but if the current working directory has a named
     directory as its prefix, that part is replaced by a `~' followed by
     the name of the directory.  If it starts with $HOME, that part is
     replaced by a `~'.

%h
%!
     Current history event number.

%i
     The line number currently being executed in the script, sourced
     file, or shell function given by %N.  This is most useful for
     debugging as part of $PS4.

%I
     The line number currently being executed in the file %x.  This is
     similar to %i, but the line number is always a line number in the
     file where the code was defined, even if the code is a shell
     function.

%j
     The number of jobs.

%L
     The current value of $SHLVL.

%N
     The name of the script, sourced file, or shell function that zsh is
     currently executing, whichever was started most recently.  If
     there is none, this is equivalent to the parameter $0.  An integer
     may follow the `%' to specify a number of trailing path components
     to show; zero means the full path.  A negative integer specifies
     leading components.

%x
     The name of the file containing the source code currently being
     executed.  This behaves as %N except that function and eval command
     names are not shown, instead the file where they were defined.

%c
%.
%C
     Trailing component of the current working directory.  An integer
     may follow the `%' to get more than one component.  Unless `%C' is
     used, tilde contraction is performed first.  These are deprecated
     as %c and %C are equivalent to %1~ and %1/, respectively, while
     explicit positive integers have the same effect as for the latter
     two sequences.



13.2.4 Date and time
--------------------


%D
     The date in YY-MM-DD format.

%T
     Current time of day, in 24-hour format.

%t
%@
     Current time of day, in 12-hour, am/pm format.

%*
     Current time of day in 24-hour format, with seconds.

%w
     The date in DAY-DD format.

%W
     The date in MM/DD/YY format.

%D{STRING}
     STRING is formatted using the strftime function.  See man page
     strftime(3) for more details.  Various zsh extensions provide
     numbers with no leading zero or space if the number is a single
     digit:


    %f
          a day of the month

    %K
          the hour of the day on the 24-hour clock

    %L
          the hour of the day on the 12-hour clock

     The GNU extension that a `-' between the % and the format
     character causes a leading zero or space to be stripped is handled
     directly by the shell for the format characters d, f, H, k, l, m,
     M, S and y; any other format characters are provided to strftime()
     with any leading `-', present, so the handling is system
     dependent.  Further GNU extensions are not supported at present.



13.2.5 Visual effects
---------------------


%B (%b)
     Start (stop) boldface mode.

%E
     Clear to end of line.

%U (%u)
     Start (stop) underline mode.

%S (%s)
     Start (stop) standout mode.

%F (%f)
     Start (stop) using a different foreground colour, if supported by
     the terminal.  The colour may be specified two ways: either as a
     numeric argument, as normal, or by a sequence in braces following
     the %F, for example %F{red}.  In the latter case the values
     allowed are as described for the fg zle_highlight attribute; *note
     Character Highlighting::.  This means that numeric colours are
     allowed in the second format also.

%K (%k)
     Start (stop) using a different bacKground colour.  The syntax is
     identical to that for %F and %f.

%{...%}
     Include a string as a literal escape sequence.  The string within
     the braces should not change the cursor position.  Brace pairs can
     nest.

     A positive numeric argument between the % and the { is treated as
     described for %G below.

%G
     Within a %{...%} sequence, include a `glitch': that is, assume
     that a single character width will be output.  This is useful when
     outputting characters that otherwise cannot be correctly handled
     by the shell, such as the alternate character set on some
     terminals.  The characters in question can be included within a
     %{...%} sequence together with the appropriate number of %G
     sequences to indicate the correct width.  An integer between the
     `%' and `G' indicates a character width other than one.  Hence
     %{SEQ%2G%} outputs SEQ and assumes it takes up the width of two
     standard characters.

     Multiple uses of %G accumulate in the obvious fashion; the position
     of the %G is unimportant.  Negative integers are not handled.

     Note that when prompt truncation is in use it is advisable to
     divide up output into single characters within each %{...%} group
     so that the correct truncation point can be found.



13.3 Conditional Substrings in Prompts
======================================


%v
     The value of the first element of the psvar array parameter.
     Following the `%' with an integer gives that element of the array.
     Negative integers count from the end of the array.

%(X.TRUE-TEXT.FALSE-TEXT)
     Specifies a ternary expression.  The character following the X is
     arbitrary; the same character is used to separate the text for the
     `true' result from that for the `false' result.  This separator
     may not appear in the TRUE-TEXT, except as part of a %-escape
     sequence.  A `)' may appear in the FALSE-TEXT as `%)'.  TRUE-TEXT
     and FALSE-TEXT may both contain arbitrarily-nested escape
     sequences, including further ternary expressions.

     The left parenthesis may be preceded or followed by a positive
     integer N, which defaults to zero.  A negative integer will be
     multiplied by -1.  The test character X may be any of the
     following:


    !
          True if the shell is running with privileges.

    #
          True if the effective uid of the current process is N.

    ?
          True if the exit status of the last command was N.

    _
          True if at least N shell constructs were started.

    C
    /
          True if the current absolute path has at least N elements
          relative to the root directory, hence / is counted as 0
          elements.

    c
    .
    ~
          True if the current path, with prefix replacement, has at
          least N elements relative to the root directory, hence / is
          counted as 0 elements.

    D
          True if the month is equal to N (January = 0).

    d
          True if the day of the month is equal to N.

    g
          True if the effective gid of the current process is N.

    j
          True if the number of jobs is at least N.

    L
          True if the SHLVL parameter is at least N.

    l
          True if at least N characters have already been printed on
          the current line.

    S
          True if the SECONDS parameter is at least N.

    T
          True if the time in hours is equal to N.

    t
          True if the time in minutes is equal to N.

    v
          True if the array psvar has at least N elements.

    V
          True if element N of the array psvar is set and non-empty.

    w
          True if the day of the week is equal to N (Sunday = 0).

%<STRING<
%>STRING>
%[XSTRING]
     Specifies truncation behaviour for the remainder of the prompt
     string.  The third, deprecated, form is equivalent to `%XSTRINGX',
     i.e. X may be `<' or `>'.  The numeric argument, which in the
     third form may appear immediately after the `[', specifies the
     maximum permitted length of the various strings that can be
     displayed in the prompt.  The STRING will be displayed in place of
     the truncated portion of any string; note this does not undergo
     prompt expansion.

     The forms with `<' truncate at the left of the string, and the
     forms with `>' truncate at the right of the string.  For example,
     if the current directory is `/home/pike', the prompt `%8<..<%/'
     will expand to `..e/pike'.  In this string, the terminating
     character (`<', `>' or `]'), or in fact any character, may be
     quoted by a preceding `\'; note when using print -P, however, that
     this must be doubled as the string is also subject to standard
     print processing, in addition to any backslashes removed by a
     double quoted string:  the worst case is therefore `print -P
     "%<\\\\<<..."'.

     If the STRING is longer than the specified truncation length, it
     will appear in full, completely replacing the truncated string.

     The part of the prompt string to be truncated runs to the end of
     the string, or to the end of the next enclosing group of the `%('
     construct, or to the next truncation encountered at the same
     grouping level (i.e. truncations inside a `%(' are separate), which
     ever comes first.  In particular, a truncation with argument zero
     (e.g. `%<<') marks the end of the range of the string to be
     truncated while turning off truncation from there on. For example,
     the prompt '%10<...<%~%<<%# ' will print a truncated
     representation of the current directory, followed by a `%' or `#',
     followed by a space.  Without the `%<<', those two characters
     would be included in the string to be truncated.


File: zsh.info,  Node: Expansion,  Next: Parameters,  Prev: Prompt Expansion,  Up: Top

14 Expansion
************



   The following types of expansions are performed in the indicated
order in five steps:


_History Expansion_
     This is performed only in interactive shells.

_Alias Expansion_
     Aliases are expanded immediately before the command line is parsed
     as explained in *note Aliasing::.

_Process Substitution_
_Parameter Expansion_
_Command Substitution_
_Arithmetic Expansion_
_Brace Expansion_
     These five are performed in one step in left-to-right fashion.
     After these expansions, all unquoted occurrences of the characters
     `\', `'' and `"' are removed.

_Filename Expansion_
     If the SH_FILE_EXPANSION option is set, the order of expansion is
     modified for compatibility with `sh' and `ksh'.  In that case
     _filename expansion_ is performed immediately after _alias
     expansion_, preceding the set of five expansions mentioned above.

_Filename Generation_
     This expansion, commonly referred to as `globbing', is always done
     last.


The following sections explain the types of expansion in detail.



* Menu:

* History Expansion::
* Process Substitution::
* Parameter Expansion::
* Command Substitution::
* Arithmetic Expansion::
* Brace Expansion::
* Filename Expansion::
* Filename Generation::

File: zsh.info,  Node: History Expansion,  Next: Process Substitution,  Up: Expansion

14.1 History Expansion
======================

History expansion allows you to use words from previous command lines
in the command line you are typing.  This simplifies spelling
corrections and the repetition of complicated commands or arguments.  Immediately
before execution, each command is saved in the history list, the size
of which is controlled by the HISTSIZE parameter.  The one most recent
command is always retained in any case.  Each saved command in the
history list is called a history _event_ and is assigned a number,
beginning with 1 (one) when the shell starts up.  The history number
that you may see in your prompt (see *note Prompt Expansion::) is the
number that is to be assigned to the _next_ command.



* Menu:

* Overview::
* Event Designators::
* Word Designators::
* Modifiers::

File: zsh.info,  Node: Overview,  Next: Event Designators,  Up: History Expansion

14.1.1 Overview
---------------

A history expansion begins with the first character of the histchars
parameter, which is `!' by default, and may occur anywhere on the
command line; history expansions do not nest.  The `!' can be escaped
with `\' or can be enclosed between a pair of single quotes ('') to
suppress its special meaning.  Double quotes will _not_ work for this.
Following this history character is an optional event designator (*note
Event Designators::) and then an optional word designator (*note Word
Designators::); if neither of these designators is present, no history
expansion occurs.

Input lines containing history expansions are echoed after being
expanded, but before any other expansions take place and before the
command is executed.  It is this expanded form that is recorded as the
history event for later references.

By default, a history reference with no event designator refers to the
same event as any preceding history reference on that command line; if
it is the only history reference in a command, it refers to the previous
command.  However, if the option CSH_JUNKIE_HISTORY is set, then every
history reference with no event specification _always_ refers to the
previous command.

For example, `!' is the event designator for the previous command, so
`!!:1' always refers to the first word of the previous command, and
`!!$' always refers to the last word of the previous command.  With
CSH_JUNKIE_HISTORY set, then `!:1' and `!$' function in the same manner
as `!!:1' and `!!$', respectively.  Conversely, if CSH_JUNKIE_HISTORY
is unset, then `!:1' and `!$' refer to the first and last words,
respectively, of the same event referenced by the nearest other history
reference preceding them on the current command line, or to the
previous command if there is no preceding reference.

The character sequence `^FOO^BAR' (where `^' is actually the second
character of the histchars parameter) repeats the last command,
replacing the string FOO with BAR.  More precisely, the sequence
`^FOO^BAR^' is synonymous with `!!:s^FOO^BAR^', hence other modifiers
(see *note Modifiers::) may follow the final `^'.  In particular,
`^FOO^BAR^:G' performs a global substitution.

If the shell encounters the character sequence `!"'  in the input, the
history mechanism is temporarily disabled until the current list (see
*note Shell Grammar::) is fully parsed.  The `!"' is removed from the
input, and any subsequent `!' characters have no special significance.

A less convenient but more comprehensible form of command history
support is provided by the fc builtin.

File: zsh.info,  Node: Event Designators,  Next: Word Designators,  Prev: Overview,  Up: History Expansion

14.1.2 Event Designators
------------------------

An event designator is a reference to a command-line entry in the
history list.  In the list below, remember that the initial `!' in each
item may be changed to another character by setting the histchars
parameter.


!
     Start a history expansion, except when followed by a blank,
     newline, `=' or `('.  If followed immediately by a word designator
     (*note Word Designators::), this forms a history reference with no
     event designator (*note Overview::).

!!
     Refer to the previous command.  By itself, this expansion repeats
     the previous command.

!N
     Refer to command-line N.

!-N
     Refer to the current command-line minus N.

!STR
     Refer to the most recent command starting with STR.

!?STR[?]
     Refer to the most recent command containing STR.  The trailing `?'
     is necessary if this reference is to be followed by a modifier or
     followed by any text that is not to be considered part of STR.

!#
     Refer to the current command line typed in so far.  The line is
     treated as if it were complete up to and including the word before
     the one with the `!#' reference.

!{...}
     Insulate a history reference from adjacent characters (if
     necessary).


File: zsh.info,  Node: Word Designators,  Next: Modifiers,  Prev: Event Designators,  Up: History Expansion

14.1.3 Word Designators
-----------------------

A word designator indicates which word or words of a given command line
are to be included in a history reference.  A `:' usually separates the
event specification from the word designator.  It may be omitted only
if the word designator begins with a `^', `$', `*', `-' or `%'.  Word
designators include:


0
     The first input word (command).

N
     The Nth argument.

^
     The first argument.  That is, 1.

$
     The last argument.

%
     The word matched by (the most recent) ?STR search.

X-Y
     A range of words; X defaults to 0.

*
     All the arguments, or a null value if there are none.

X*
     Abbreviates `X-$'.

X-
     Like `X*' but omitting word $.

Note that a `%' word designator works only when used in one of `!%',
`!:%' or `!?STR?:%', and only when used after a !? expansion (possibly
in an earlier command).  Anything else results in an error, although
the error may not be the most obvious one.

File: zsh.info,  Node: Modifiers,  Prev: Word Designators,  Up: History Expansion

14.1.4 Modifiers
----------------

After the optional word designator, you can add a sequence of one or
more of the following modifiers, each preceded by a `:'.  These
modifiers also work on the result of _filename generation_ and
_parameter expansion_, except where noted.


a
     Turn a file name into an absolute path:  prepends the current
     directory, if necessary, and resolves any use of `..' and `.' in
     the path.  Note that the transformation takes place even if the
     file or any intervening directories do not exist.

A
     As `a', but also resolve use of symbolic links where possible.
     Note that resolution of `..' occurs _before_ resolution of symbolic
     links.  This call is equivalent to a unless your system has the
     realpath system call (modern systems do).

c
     Resolve a command name into an absolute path by searching the
     command path given by the PATH variable.  This does not work for
     commands containing directory parts.  Note also that this does not
     usually work as a glob qualifier unless a file of the same name is
     found in the current directory.

e
     Remove all but the extension.

h
     Remove a trailing pathname component, leaving the head.  This works
     like `dirname'.

l
     Convert the words to all lowercase.

p
     Print the new command but do not execute it.  Only works with
     history expansion.

q
     Quote the substituted words, escaping further substitutions.  Works
     with history expansion and parameter expansion, though for
     parameters it is only useful if the resulting text is to be
     re-evaluated such as by eval.

Q
     Remove one level of quotes from the substituted words.

r
     Remove a filename extension of the form `.XXX', leaving the root
     name.

s/L/R[/]
     Substitute R for L as described below.  The substitution is done
     only for the first string that matches L.  For arrays and for
     filename generation, this applies to each word of the expanded
     text.  See below for further notes on substitutions.

     The forms `gs/L/R' and `s/L/R/:G' perform global substitution,
     i.e. substitute every occurrence of R for L.  Note that the g or
     :G must appear in exactly the position shown.

     See further notes on this form of substitution below.

&
     Repeat the previous s substitution.  Like s, may be preceded
     immediately by a g.  In parameter expansion the & must appear
     inside braces, and in filename generation it must be quoted with a
     backslash.

t
     Remove all leading pathname components, leaving the tail.  This
     works like `basename'.

u
     Convert the words to all uppercase.

x
     Like q, but break into words at whitespace.  Does not work with
     parameter expansion.


The s/L/R/ substitution works as follows.  By default the left-hand
side of substitutions are not patterns, but character strings.  Any
character can be used as the delimiter in place of `/'.  A backslash
quotes the delimiter character.  The character `&', in the
right-hand-side R, is replaced by the text from the left-hand-side L.
The `&' can be quoted with a backslash.  A null L uses the previous
string either from the previous L or from the contextual scan string S
from `!?S'.  You can omit the rightmost delimiter if a newline
immediately follows R; the rightmost `?' in a context scan can
similarly be omitted.  Note the same record of the last L and R is
maintained across all forms of expansion.

Note that if a `&' is used within glob qualifers an extra backslash is
needed as a & is a special character in this case.

If the option HIST_SUBST_PATTERN is set, L is treated as a pattern of
the usual form described in *note Filename Generation::.  This can be
used in all the places where modifiers are available; note, however,
that in globbing qualifiers parameter substitution has already taken
place, so parameters in the replacement string should be quoted to
ensure they are replaced at the correct time.  Note also that
complicated patterns used in globbing qualifiers may need the extended
glob qualifier notation (#q:s/.../.../) in order for the shell to
recognize the expression as a glob qualifier.  Further, note that bad
patterns in the substitution are not subject to the NO_BAD_PATTERN
option so will cause an error.

When HIST_SUBST_PATTERN is set, L may start with a # to indicate that
the pattern must match at the start of the string to be substituted,
and a % may appear at the start or after an # to indicate that the
pattern must match at the end of the string to be substituted.  The %
or # may be quoted with two backslashes.

For example, the following piece of filename generation code with the
EXTENDED_GLOB option:


     print *.c(#q:s/#%(#b)s(*).c/'S${match[1]}.C'/)

takes the expansion of *.c and applies the glob qualifiers in the
(#q...) expression, which consists of a substitution modifier anchored
to the start and end of each word (#%).  This turns on backreferences
((#b)), so that the parenthesised subexpression is available in the
replacement string as ${match[1]}.  The replacement string is quoted so
that the parameter is not substituted before the start of filename
generation.

The following f, F, w and W modifiers work only with parameter
expansion and filename generation.  They are listed here to provide a
single point of reference for all modifiers.


f
     Repeats the immediately (without a colon) following modifier until
     the resulting word doesn't change any more.

F:EXPR:
     Like f, but repeats only N times if the expression EXPR evaluates
     to N.  Any character can be used instead of the `:'; if `(', `[',
     or `{' is used as the opening delimiter, the closing delimiter
     should be ')', `]', or `}', respectively.

w
     Makes the immediately following modifier work on each word in the
     string.

W:SEP:
     Like w but words are considered to be the parts of the string that
     are separated by SEP. Any character can be used instead of the
     `:'; opening parentheses are handled specially, see above.


File: zsh.info,  Node: Process Substitution,  Next: Parameter Expansion,  Prev: History Expansion,  Up: Expansion

14.2 Process Substitution
=========================

Each part of a command argument that takes the form `<(LIST)',
`>(LIST)' or `=(LIST)' is subject to process substitution.  The
expression may be preceeded or followed by other strings except that,
to prevent clashes with commonly occurring strings and patterns, the
last form must occur at the start of a command argument, and the forms
are only expanded when first parsing command or assignment arguments.
Process substitutions may be used following redirection operators; in
this case, the substitution must appear with no trailing string.

In the case of the < or > forms, the shell runs the commands in LIST as
a subprocess of the job executing the shell command line.  If the
system supports the /dev/fd mechanism, the command argument is the name
of the device file corresponding to a file descriptor; otherwise, if
the system supports named pipes (FIFOs), the command argument will be a
named pipe.  If the form with > is selected then writing on this
special file will provide input for LIST.  If < is used, then the file
passed as an argument will be connected to the output of the LIST
process.  For example,


     paste <(cut -f1 FILE1) <(cut -f3 FILE2) |
     tee >(PROCESS1) >(PROCESS2) >/dev/null

cuts fields 1 and 3 from the files FILE1 and FILE2 respectively, pastes
the results together, and sends it to the processes PROCESS1 and
PROCESS2.

If =(...) is used instead of <(...), then the file passed as an
argument will be the name of a temporary file containing the output of
the LIST process.  This may be used instead of the < form for a program
that expects to lseek (see man page lseek(2)) on the input file.

There is an optimisation for substitutions of the form =(<<<ARG), where
ARG is a single-word argument to the here-string redirection <<<.  This
form produces a file name containing the value of ARG after any
substitutions have been performed.  This is handled entirely within the
current shell.  This is effectively the reverse of the special form
$(<ARG) which treats ARG as a file name and replaces it with the file's
contents.

The = form is useful as both the /dev/fd and the named pipe
implementation of <(...) have drawbacks.  In the former case, some
programmes may automatically close the file descriptor in question
before examining the file on the command line, particularly if this is
necessary for security reasons such as when the programme is running
setuid.  In the second case, if the programme does not actually open
the file, the subshell attempting to read from or write to the pipe
will (in a typical implementation, different operating systems may have
different behaviour) block for ever and have to be killed explicitly.
In both cases, the shell actually supplies the information using a
pipe, so that programmes that expect to lseek (see man page lseek(2))
on the file will not work.

Also note that the previous example can be more compactly and
efficiently written (provided the MULTIOS option is set) as:


     paste <(cut -f1 FILE1) <(cut -f3 FILE2) > >(PROCESS1) > >(PROCESS2)

The shell uses pipes instead of FIFOs to implement the latter two
process substitutions in the above example.

There is an additional problem with >(PROCESS); when this is attached
to an external command, the parent shell does not wait for PROCESS to
finish and hence an immediately following command cannot rely on the
results being complete.  The problem and solution are the same as
described in the section _MULTIOS_ in *note Redirection::.  Hence in a
simplified version of the example above:


     paste <(cut -f1 FILE1) <(cut -f3 FILE2) > >(PROCESS)

(note that no MULTIOS are involved), PROCESS will be run asynchronously
as far as the parent shell is concerned.  The workaround is:


     { paste <(cut -f1 FILE1) <(cut -f3 FILE2) } > >(PROCESS)

The extra processes here are spawned from the parent shell which will
wait for their completion.



File: zsh.info,  Node: Parameter Expansion,  Next: Command Substitution,  Prev: Process Substitution,  Up: Expansion

14.3 Parameter Expansion
========================

The character `$' is used to introduce parameter expansions.  See *note
Parameters:: for a description of parameters, including arrays,
associative arrays, and subscript notation to access individual array
elements.

Note in particular the fact that words of unquoted parameters are not
automatically split on whitespace unless the option SH_WORD_SPLIT is
set; see references to this option below for more details.  This is an
important difference from other shells.

In the expansions discussed below that require a pattern, the form of
the pattern is the same as that used for filename generation; see *note
Filename Generation::.  Note that these patterns, along with the
replacement text of any substitutions, are themselves subject to
parameter expansion, command substitution, and arithmetic expansion.
In addition to the following operations, the colon modifiers described
in *note Modifiers:: in *note History Expansion:: can be applied:  for
example, ${i:s/foo/bar/} performs string substitution on the expansion
of parameter $i.


${NAME}
     The value, if any, of the parameter NAME is substituted.  The
     braces are required if the expansion is to be followed by a
     letter, digit, or underscore that is not to be interpreted as part
     of NAME.  In addition, more complicated forms of substitution
     usually require the braces to be present; exceptions, which only
     apply if the option KSH_ARRAYS is not set, are a single subscript
     or any colon modifiers appearing after the name, or any of the
     characters `^', `=', `~', `#' or `+' appearing before the name,
     all of which work with or without braces.

     If NAME is an array parameter, and the KSH_ARRAYS option is not
     set, then the value of each element of NAME is substituted, one
     element per word.  Otherwise, the expansion results in one word
     only; with KSH_ARRAYS, this is the first element of an array.  No
     field splitting is done on the result unless the SH_WORD_SPLIT
     option is set.  See also the flags = and s:STRING:.

${+NAME}
     If NAME is the name of a set parameter `1' is substituted,
     otherwise `0' is substituted.

${NAME-WORD}
${NAME:-WORD}
     If NAME is set, or in the second form is non-null, then substitute
     its value; otherwise substitute WORD.  In the second form NAME may
     be omitted, in which case WORD is always substituted.

${NAME+WORD}
${NAME:+WORD}
     If NAME is set, or in the second form is non-null, then substitute
     WORD; otherwise substitute nothing.

${NAME=WORD}
${NAME:=WORD}
${NAME::=WORD}
     In the first form, if NAME is unset then set it to WORD; in the
     second form, if NAME is unset or null then set it to WORD; and in
     the third form, unconditionally set NAME to WORD.  In all forms,
     the value of the parameter is then substituted.

${NAME?WORD}
${NAME:?WORD}
     In the first form, if NAME is set, or in the second form if NAME
     is both set and non-null, then substitute its value; otherwise,
     print WORD and exit from the shell.  Interactive shells instead
     return to the prompt.  If WORD is omitted, then a standard message
     is printed.


In any of the above expressions that test a variable and substitute an
alternate WORD, note that you can use standard shell quoting in the
WORD value to selectively override the splitting done by the
SH_WORD_SPLIT option and the = flag, but not splitting by the s:STRING:
flag.

In the following expressions, when NAME is an array and the
substitution is not quoted, or if the `(@)' flag or the NAME[@] syntax
is used, matching and replacement is performed on each array element
separately.


${NAME#PATTERN}
${NAME##PATTERN}
     If the PATTERN matches the beginning of the value of NAME, then
     substitute the value of NAME with the matched portion deleted;
     otherwise, just substitute the value of NAME.  In the first form,
     the smallest matching pattern is preferred; in the second form,
     the largest matching pattern is preferred.

${NAME%PATTERN}
${NAME%%PATTERN}
     If the PATTERN matches the end of the value of NAME, then
     substitute the value of NAME with the matched portion deleted;
     otherwise, just substitute the value of NAME.  In the first form,
     the smallest matching pattern is preferred; in the second form,
     the largest matching pattern is preferred.

${NAME:#PATTERN}
     If the PATTERN matches the value of NAME, then substitute the
     empty string; otherwise, just substitute the value of NAME.  If
     NAME is an array the matching array elements are removed (use the
     `(M)' flag to remove the non-matched elements).

${NAME:OFFSET}
${NAME:OFFSET:LENGTH}
     This syntax gives effects similar to parameter subscripting in the
     form $NAME{START,END}, but is compatible with other shells; note
     that both OFFSET and LENGTH are interpreted differently from the
     components of a subscript.

     If OFFSET is non-negative, then if the variable NAME is a scalar
     substitute the contents starting OFFSET characters from the first
     character of the string, and if NAME is an array substitute
     elements starting OFFSET elements from the first element.  If
     LENGTH is given, substitute that many characters or elements,
     otherwise the entire rest of the scalar or array.

     A positive OFFSET is always treated as the offset of a character or
     element in NAME from the first character or element of the array
     (this is different from native zsh subscript notation).  Hence 0
     refers to the first character or element regardless of the setting
     of the option KSH_ARRAYS.

     A negative offset counts backwards from the end of the scalar or
     array, so that -1 corresponds to the last character or element,
     and so on.

     LENGTH is always treated directly as a length and hence may not be
     negative.  The option MULTIBYTE is obeyed, i.e. the offset and
     length count multibyte characters where appropriate.

     OFFSET and LENGTH undergo the same set of shell substitutions as
     for scalar assignment; in addition, they are then subject to
     arithmetic evaluation.  Hence, for example


          print ${foo:3}
          print ${foo: 1 + 2}
          print ${foo:$(( 1 + 2))}
          print ${foo:$(echo 1 + 2)}

     all have the same effect, extracting the string starting at the
     fourth character of $foo if the substution would otherwise return
     a scalar, or the array starting at the fourth element if $foo
     would return an array.  Note that with the option KSH_ARRAYS $foo
     always returns a scalar (regardless of the use of the offset
     syntax) and a form such as $foo[*]:3 is required to extract
     elements of an array named foo.

     If OFFSET is negative, the - may not appear immediately after the
     : as this indicates the ${NAME:-WORD} form of substitution.
     Instead, a space may be inserted before the -.  Furthermore,
     neither OFFSET nor LENGTH may begin with an alphabetic character
     or & as these are used to indicate history-style modifiers.  To
     substitute a value from a variable, the recommended approach is to
     proceed it with a $ as this signifies the intention (parameter
     substitution can easily be rendered unreadable); however, as
     arithmetic substitution is performed, the expression ${var: offs}
     does work, retrieving the offset from $offs.

     For further compatibility with other shells there is a special case
     for array offset 0.  This usually accesses to the first element of
     the array.  However, if the substitution refers the positional
     parameter array, e.g. $@ or $*, then offset 0 instead refers to
     $0, offset 1 refers to $1, and so on.  In other words, the
     positional parameter array is effectively extended by prepending
     $0.  Hence ${*:0:1} substitutes $0 and ${*:1:1} substitutes $1.

${NAME/PATTERN/REPL}
${NAME//PATTERN/REPL}
     Replace the longest possible match of PATTERN in the expansion of
     parameter NAME by string REPL.  The first form replaces just the
     first occurrence, the second form all occurrences.  Both PATTERN
     and REPL are subject to double-quoted substitution, so that
     expressions like ${name/$opat/$npat} will work, but note the usual
     rule that pattern characters in $opat are not treated specially
     unless either the option GLOB_SUBST is set, or $opat is instead
     substituted as ${~opat}.

     The PATTERN may begin with a `#', in which case the PATTERN must
     match at the start of the string, or `%', in which case it must
     match at the end of the string, or `#%' in which case the PATTERN
     must match the entire string.  The REPL may be an empty string, in
     which case the final `/' may also be omitted.  To quote the final
     `/' in other cases it should be preceded by a single backslash;
     this is not necessary if the `/' occurs inside a substituted
     parameter.  Note also that the `#', `%' and `#% are not active if
     they occur inside a substituted parameter, even at the start.

     The first `/' may be preceded by a `:', in which case the match
     will only succeed if it matches the entire word.  Note also the
     effect of the I and S parameter expansion flags below; however,
     the flags M, R, B, E and N are not useful.

     For example,


          foo="twinkle twinkle little star" sub="t*e" rep="spy"
          print ${foo//${~sub}/$rep}
          print ${(S)foo//${~sub}/$rep}

     Here, the `~' ensures that the text of $sub is treated as a
     pattern rather than a plain string.  In the first case, the longest
     match for t*e is substituted and the result is `spy star', while
     in the second case, the shortest matches are taken and the result
     is `spy spy lispy star'.

${#SPEC}
     If SPEC is one of the above substitutions, substitute the length
     in characters of the result instead of the result itself.  If SPEC
     is an array expression, substitute the number of elements of the
     result.  Note that `^', `=', and `~', below, must appear to the
     left of `#' when these forms are combined.

${^SPEC}
     Turn on the RC_EXPAND_PARAM option for the evaluation of SPEC; if
     the `^' is doubled, turn it off.  When this option is set, array
     expansions of the form FOO${XX}BAR, where the parameter XX is set
     to (A B C), are substituted with `FOOABAR FOOBBAR FOOCBAR' instead
     of the default `FOOA B CBAR'.  Note that an empty array will
     therefore cause all arguments to be removed.

     Internally, each such expansion is converted into the equivalent
     list for brace expansion.  E.g., ${^var} becomes
     {$var[1],$var[2],...}, and is processed as described in *note
     Brace Expansion:: below.  If word splitting is also in effect the
     $var[N] may themselves be split into different list elements.

${=SPEC}
     Perform word splitting using the rules for SH_WORD_SPLIT during the
     evaluation of SPEC, but regardless of whether the parameter
     appears in double quotes; if the `=' is doubled, turn it off.  This
     forces parameter expansions to be split into separate words before
     substitution, using IFS as a delimiter.  This is done by default
     in most other shells.

     Note that splitting is applied to WORD in the assignment forms of
     SPEC _before_ the assignment to NAME is performed.  This affects
     the result of array assignments with the A flag.

${~SPEC}
     Turn on the GLOB_SUBST option for the evaluation of SPEC; if the
     `~' is doubled, turn it off.  When this option is set, the string
     resulting from the expansion will be interpreted as a pattern
     anywhere that is possible, such as in filename expansion and
     filename generation and pattern-matching contexts like the right
     hand side of the `=' and `!=' operators in conditions.

     In nested substitutions, note that the effect of the ~ applies to
     the result of the current level of substitution.  A surrounding
     pattern operation on the result may cancel it.  Hence, for
     example, if the parameter foo is set to *, ${~foo//\*/*.c} is
     substituted by the pattern *.c, which may be expanded by filename
     generation, but ${${~foo}//\*/*.c} substitutes to the string *.c,
     which will not be further expanded.


If a ${...} type parameter expression or a $(...) type command
substitution is used in place of NAME above, it is expanded first and
the result is used as if it were the value of NAME.  Thus it is
possible to perform nested operations:  ${${foo#head}%tail} substitutes
the value of $foo with both `head' and `tail' deleted.  The form with
$(...) is often useful in combination with the flags described next;
see the examples below.  Each NAME or nested ${...} in a parameter
expansion may also be followed by a subscript expression as described in
*note Array Parameters::.

Note that double quotes may appear around nested expressions, in which
case only the part inside is treated as quoted; for example,
${(f)"$(foo)"} quotes the result of $(foo), but the flag `(f)' (see
below) is applied using the rules for unquoted expansions.  Note
further that quotes are themselves nested in this context; for example,
in "${(@f)"$(foo)"}", there are two sets of quotes, one surrounding the
whole expression, the other (redundant) surrounding the $(foo) as
before.



14.3.1 Parameter Expansion Flags
--------------------------------

If the opening brace is directly followed by an opening parenthesis,
the string up to the matching closing parenthesis will be taken as a
list of flags.  In cases where repeating a flag is meaningful, the
repetitions need not be consecutive; for example, `(q%q%q)' means the
same thing as the more readable `(%%qqq)'.  The following flags are
supported:


#
     Evaluate the resulting words as numeric expressions and output the
     characters corresponding to the resulting integer.  Note that this
     form is entirely distinct from use of the # without parentheses.

     If the MULTIBYTE option is set and the number is greater than 127
     (i.e. not an ASCII character) it is treated as a Unicode character.

%
     Expand all % escapes in the resulting words in the same way as in
     prompts (see *note Prompt Expansion::). If this flag is given
     twice, full prompt expansion is done on the resulting words,
     depending on the setting of the PROMPT_PERCENT, PROMPT_SUBST and
     PROMPT_BANG options.

@
     In double quotes, array elements are put into separate words.
     E.g., `"${(@)foo}"' is equivalent to `"${foo[@]}"' and
     `"${(@)foo[1,2]}"' is the same as `"$foo[1]" "$foo[2]"'.  This is
     distinct from _field splitting_ by the the f, s or z flags, which
     still applies within each array element.

A
     Create an array parameter with `${...=...}', `${...:=...}' or
     `${...::=...}'.  If this flag is repeated (as in `AA'), create an
     associative array parameter.  Assignment is made before sorting or
     padding.  The NAME part may be a subscripted range for ordinary
     arrays; the WORD part _must_ be converted to an array, for example
     by using `${(AA)=NAME=...}' to activate field splitting, when
     creating an associative array.

a
     Sort in array index order; when combined with `O' sort in reverse
     array index order.  Note that `a' is therefore equivalent to the
     default but `Oa' is useful for obtaining an array's elements in
     reverse order.

c
     With ${#NAME}, count the total number of characters in an array,
     as if the elements were concatenated with spaces between them.

C
     Capitalize the resulting words.  `Words' in this case refers to
     sequences of alphanumeric characters separated by
     non-alphanumerics, _not_ to words that result from field splitting.

D
     Assume the string or array elements contain directories and attempt
     to substitute the leading part of these by names.  The remainder of
     the path (the whole of it if the leading part was not subsituted)
     is then quoted so that the whole string can be used as a shell
     argument.  This is the reverse of `~' substitution:  see *note
     Filename Expansion::.

e
     Perform _parameter expansion_, _command substitution_ and
     _arithmetic expansion_ on the result. Such expansions can be
     nested but too deep recursion may have unpredictable effects.

f
     Split the result of the expansion at newlines. This is a shorthand
     for `ps:\n:'.

F
     Join the words of arrays together using newline as a separator.
     This is a shorthand for `pj:\n:'.

i
     Sort case-insensitively.  May be combined with `n' or `O'.

k
     If NAME refers to an associative array, substitute the _keys_
     (element names) rather than the values of the elements.  Used with
     subscripts (including ordinary arrays), force indices or keys to be
     substituted even if the subscript form refers to values.  However,
     this flag may not be combined with subscript ranges.

L
     Convert all letters in the result to lower case.

n
     Sort decimal integers numerically; if the first differing
     characters of two test strings are not digits, sorting is lexical.
      Integers with more initial zeroes are sorted before those with
     fewer or none.  Hence the array `foo1 foo02 foo2 foo3 foo20 foo23'
     is sorted into the order shown.  May be combined with `i' or `O'.

o
     Sort the resulting words in ascending order; if this appears on its
     own the sorting is lexical and case-sensitive (unless the locale
     renders it case-insensitive).  Sorting in ascending order is the
     default for other forms of sorting, so this is ignored if combined
     with `a', `i' or `n'.

O
     Sort the resulting words in descending order; `O' without `a', `i'
     or `n' sorts in reverse lexical order.  May be combined with `a',
     `i' or `n' to reverse the order of sorting.

P
     This forces the value of the parameter NAME to be interpreted as a
     further parameter name, whose value will be used where appropriate.
     Note that flags set with one of the typeset family of commands (in
     particular case transformations) are not applied to the value of
     NAME used in this fashion.

     If used with a nested parameter or command substitution, the
     result of that will be taken as a parameter name in the same way.
     For example, if you have `foo=bar' and `bar=baz', the strings
     ${(P)foo}, ${(P)${foo}}, and ${(P)$(echo bar)} will be expanded to
     `baz'.

q
     Quote characters that are special to the shell in the resulting
     words with backslashes; unprintable or invalid characters are
     quoted using the $'\NNN' form, with separate quotes for each octet.

     If this flag is given twice, the resulting words are quoted in
     single quotes and if it is given three times, the words are quoted
     in double quotes; in these forms no special handling of
     unprintable or invalid characters is attempted.  If the flag is
     given four times, the words are quoted in single quotes preceded
     by a $.  Note that in all three of these forms quoting is done
     unconditionally, even if this does not change the way the
     resulting string would be interpreted by the shell.

     If a q- is given (only a single q may appear), a minimal form of
     single quoting is used that only quotes the string if needed to
     protect special characters.  Typically this form gives the most
     readable output.

Q
     Remove one level of quotes from the resulting words.

t
     Use a string describing the type of the parameter where the value
     of the parameter would usually appear. This string consists of
     keywords separated by hyphens (`-'). The first keyword in the
     string describes the main type, it can be one of `scalar',
     `array', `integer', `float' or `association'. The other keywords
     describe the type in more detail:


    local
          for local parameters

    left
          for left justified parameters

    right_blanks
          for right justified parameters with leading blanks

    right_zeros
          for right justified parameters with leading zeros

    lower
          for parameters whose value is converted to all lower case
          when it is expanded

    upper
          for parameters whose value is converted to all upper case
          when it is expanded

    readonly
          for readonly parameters

    tag
          for tagged parameters

    export
          for exported parameters

    unique
          for arrays which keep only the first occurrence of duplicated
          values

    hide
          for parameters with the `hide' flag

    special
          for special parameters defined by the shell


u
     Expand only the first occurrence of each unique word.

U
     Convert all letters in the result to upper case.

v
     Used with k, substitute (as two consecutive words) both the key
     and the value of each associative array element.  Used with
     subscripts, force values to be substituted even if the subscript
     form refers to indices or keys.

V
     Make any special characters in the resulting words visible.

w
     With ${#NAME}, count words in arrays or strings; the s flag may be
     used to set a word delimiter.

W
     Similar to w with the difference that empty words between repeated
     delimiters are also counted.

X
     With this flag, parsing errors occurring with the Q, e and # flags
     or the pattern matching forms such as `${NAME#PATTERN}' are
     reported.  Without the flag, errors are silently ignored.

z
     Split the result of the expansion into words using shell parsing to
     find the words, i.e. taking into account any quoting in the value.
     Comments are not treated specially but as ordinary strings, similar
     to interactive shells with the INTERACTIVE_COMMENTS option unset.

     Note that this is done very late, as for the `(s)' flag. So to
     access single words in the result, one has to use nested
     expansions as in `${${(z)foo}[2]}'. Likewise, to remove the quotes
     in the resulting words one would do: `${(Q)${(z)foo}}'.

0
     Split the result of the expansion on null bytes.  This is a
     shorthand for `ps:\0:'.


The following flags (except p) are followed by one or more arguments as
shown.  Any character, or the matching pairs `(...)', `{...}', `[...]',
or `<...>', may be used in place of a colon as delimiters, but note
that when a flag takes more than one argument, a matched pair of
delimiters must surround each argument.


p
     Recognize the same escape sequences as the print builtin in string
     arguments to any of the flags described below that follow this
     argument.

~
     Force string arguments to any of the flags below that follow within
     the parentheses to be treated as patterns.  Compare with a ~
     outside parentheses, which forces the entire substituted string to
     be treated as a pattern.  Hence, for example,
          [[ "?" = ${(~j.|.)array} ]]
     with the EXTENDED_GLOB option set succeeds if and only if $array
     contains the string `?' as an element.  The argument may be
     repeated to toggle the behaviour; its effect only lasts to the end
     of the parenthesised group.

j:STRING:
     Join the words of arrays together using STRING as a separator.  Note
     that this occurs before field splitting by the s:STRING: flag or
     the SH_WORD_SPLIT option.

l:EXPR::STRING1::STRING2:
     Pad the resulting words on the left.  Each word will be truncated
     if required and placed in a field EXPR characters wide.

     The arguments :STRING1: and :STRING2: are optional; neither, the
     first, or both may be given.  Note that the same pairs of
     delimiters must be used for each of the three arguments.  The
     space to the left will be filled with STRING1 (concatenated as
     often as needed) or spaces if STRING1 is not given.  If both
     STRING1 and STRING2 are given, string2 is inserted once directly
     to the left of each word, truncated if necessary, before STRING1
     is used to produce any remaining padding.

     If the MULTIBYTE option is in effect, the flag m may also be
     given, in which case widths will be used for the calculation of
     padding; otherwise individual multibyte characters are treated as
     occupying one unit of width.

     If the MULTIBYTE option is not in effect, each byte in the string
     is treated as occupying one unit of width.

     Control characters are always assumed to be one unit wide; this
     allows the mechanism to be used for generating repetitions of
     control characters.

m
     Only useful together with one of the flags l or r or with the #
     length operator when the MULTIBYTE option is in effect.  Use the
     character width reported by the system in calculating how much of
     the string it occupies or the overall length of the string.  Most
     printable characters have a width of one unit, however certain
     Asian character sets and certain special effects use wider
     characters; combining characters have zero width.  Non-printable
     characters are arbitrarily counted as zero width; how they would
     actually be displayed will vary.

     If the m is repeated, the character either counts zero (if it has
     zero width), else one.  For printable character strings this has
     the effect of counting the number of glyphs (visibly separate
     characters), except for the case where combining characters
     themselves have non-zero width (true in certain alphabets).

r:EXPR::STRING1::STRING2:
     As l, but pad the words on the right and insert STRING2
     immediately to the right of the string to be padded.

     Left and right padding may be used together.  In this case the
     strategy is to apply left padding to the first half width of each
     of the resulting words, and right padding to the second half.  If
     the string to be padded has odd width the extra padding is applied
     on the left.

s:STRING:
     Force field splitting at the separator STRING.  Note that a STRING
     of two or more characters means that all of them must match in
     sequence; this differs from the treatment of two or more
     characters in the IFS parameter.  See also the = flag and the
     SH_WORD_SPLIT option.

     For historical reasons, the usual behaviour that empty array
     elements are retained inside double quotes is disabled for arrays
     generated by splitting; hence the following:


          line="one::three"
          print -l "${(s.:.)line}"

     produces two lines of output for one and three and elides the
     empty field.  To override this behaviour, supply the "(@)" flag as
     well, i.e.  "${(@s.:.)line}".

Z:OPTS:
     As z but takes a combination of option letters between a following
     pair of delimiter characters.  (Z+c+) causes comments to be parsed
     as a string and retained; any field in the resulting array
     beginning with an unquoted comment character is a comment.  (Z+C+)
     causes comments to be parsed and removed.  The rule for comments
     is standard: anything between a word starting with the third
     character of $HISTCHARS, default #, up to the next newline is a
     comment.  (Z+n+) causes unquoted newlines to be treated as
     ordinary whitespace, else they are treated as if they are shell
     code delimiters and converted to semicolons.

_:FLAGS:
     The underscore (_) flag is reserved for future use.  As of this
     revision of zsh, there are no valid FLAGS; anything following an
     underscore, other than an empty pair of delimiters, is treated as
     an error, and the flag itself has no effect.


The following flags are meaningful with the ${...#...} or ${...%...}
forms.  The S and I flags may also be used with the ${.../...} forms.


S
     Search substrings as well as beginnings or ends; with # start from
     the beginning and with % start from the end of the string.  With
     substitution via ${.../...} or ${...//...}, specifies non-greedy
     matching, i.e. that the shortest instead of the longest match
     should be replaced.

I:EXPR:
     Search the EXPRth match (where EXPR evaluates to a number).  This
     only applies when searching for substrings, either with the S
     flag, or with ${.../...} (only the EXPRth match is substituted) or
     ${...//...} (all matches from the EXPRth on are substituted).  The
     default is to take the first match.

     The EXPRth match is counted such that there is either one or zero
     matches from each starting position in the string, although for
     global substitution matches overlapping previous replacements are
     ignored.  With the ${...%...} and ${...%%...} forms, the starting
     position for the match moves backwards from the end as the index
     increases, while with the other forms it moves forward from the
     start.

     Hence with the string
          which switch is the right switch for Ipswich?
     substitutions of the form ${(SI:N:)string#w*ch} as N increases
     from 1 will match and remove `which', `witch', `witch' and `wich';
     the form using `##' will match and remove `which switch is the
     right switch for Ipswich', `witch is the right switch for
     Ipswich', `witch for Ipswich' and `wich'. The form using `%' will
     remove the same matches as for `#', but in reverse order, and the
     form using `%%' will remove the same matches as for `##' in reverse
     order.

B
     Include the index of the beginning of the match in the result.

E
     Include the index of the end of the match in the result.

M
     Include the matched portion in the result.

N
     Include the length of the match in the result.

R
     Include the unmatched portion in the result (the _R_est).



14.3.2 Rules
------------

Here is a summary of the rules for substitution; this assumes that
braces are present around the substitution, i.e. ${...}.  Some
particular examples are given below.  Note that the Zsh Development
Group accepts _no responsibility_ for any brain damage which may occur
during the reading of the following rules.


1. _Nested Substitution_
     If multiple nested ${...} forms are present, substitution is
     performed from the inside outwards.  At each level, the
     substitution takes account of whether the current value is a
     scalar or an array, whether the whole substitution is in double
     quotes, and what flags are supplied to the current level of
     substitution, just as if the nested substitution were the
     outermost.  The flags are not propagated up to enclosing
     substitutions; the nested substitution will return either a scalar
     or an array as determined by the flags, possibly adjusted for
     quoting.  All the following steps take place where applicable at
     all levels of substitution.  Note that, unless the `(P)' flag is
     present, the flags and any subscripts apply directly to the value
     of the nested substitution; for example, the expansion ${${foo}}
     behaves exactly the same as ${foo}.

     At each nested level of substitution, the substituted words
     undergo all forms of single-word substitution (i.e. not filename
     generation), including command substitution, arithmetic expansion
     and filename expansion (i.e. leading ~ and =).  Thus, for example,
     ${${:-=cat}:h} expands to the directory where the cat program
     resides.  (Explanation: the internal substitution has no parameter
     but a default value =cat, which is expanded by filename expansion
     to a full path; the outer substitution then applies the modifier
     :h and takes the directory part of the path.)

2. _Internal Parameter Flags_
     Any parameter flags set by one of the typeset family of commands,
     in particular the L, R, Z, u and l flags for padding and
     capitalization, are applied directly to the parameter value.

3. _Parameter Subscripting_
     If the value is a raw parameter reference with a subscript, such as
     ${VAR[3]}, the effect of subscripting is applied directly to the
     parameter.  Subscripts are evaluated left to right; subsequent
     subscripts apply to the scalar or array value yielded by the
     previous subscript.  Thus if var is an array, ${var[1][2]} is the
     second character of the first word, but ${var[2,4][2]} is the
     entire third word (the second word of the range of words two
     through four of the original array).  Any number of subscripts may
     appear.

4. _Parameter Name Replacement_
     The effect of any (P) flag, which treats the value so far as a
     parameter name and replaces it with the corresponding value, is
     applied.

5. _Double-Quoted Joining_
     If the value after this process is an array, and the substitution
     appears in double quotes, and no (@) flag is present at the current
     level, the words of the value are joined with the first character
     of the parameter $IFS, by default a space, between each word
     (single word arrays are not modified).  If the (j) flag is
     present, that is used for joining instead of $IFS.

6. _Nested Subscripting_
     Any remaining subscripts (i.e. of a nested substitution) are
     evaluated at this point, based on whether the value is an array or
     a scalar.  As with 3., multiple subscripts can appear.  Note that
     ${foo[2,4][2]} is thus equivalent to ${${foo[2,4]}[2]} and also to
     "${${(@)foo[2,4]}[2]}" (the nested substitution returns an array in
     both cases), but not to "${${foo[2,4]}[2]}" (the nested
     substitution returns a scalar because of the quotes).

7. _Modifiers_
     Any modifiers, as specified by a trailing `#', `%', `/' (possibly
     doubled) or by a set of modifiers of the form :... (see *note
     Modifiers:: in *note History Expansion::), are applied to the words
     of the value at this level.

8. _Character evaluation_
     Any (#) flag is applied, evaluating the result so far numerically
     as a character.

9. _Length_
     Any initial # modifier, i.e. in the form ${#VAR}, is used to
     evaluate the length of the expression so far.

10. _Forced Joining_
     If the `(j)' flag is present, or no `(j)' flag is present but the
     string is to be split as given by rules 16. or 17., and joining
     did not take place at step 5., any words in the value are joined
     together using the given string or the first character of $IFS if
     none.  Note that the `(F)' flag implicitly supplies a string for
     joining in this manner.

11. _Case modification_
     Any case modification from one of the flags (L), (U) or (C) is
     applied.

12. _Prompt evaluation_
     Any prompt-style formatting from the (%) family of flags is
     applied.

13. _Quote application_
     Any quoting or unquoting using (q) and (Q) and related flags is
     applied.

14. _Directory naming_
     Any directory name substitution using (D) flag is applied.

15. _Visibility enhancment_
     Any modifications to make characters visible using the (V) flag
     are applied.

16. _Forced Splitting_
     If one of the `(s)', `(f)' or `(z)' flags are present, or the `='
     specifier was present (e.g. ${=VAR}), the word is split on
     occurrences of the specified string, or (for = with neither of the
     two flags present) any of the characters in $IFS.

17. _Shell Word Splitting_
     If no `(s)', `(f)' or `=' was given, but the word is not quoted
     and the option SH_WORD_SPLIT is set, the word is split on
     occurrences of any of the characters in $IFS.  Note this step, too,
     takes place at all levels of a nested substitution.

18. _Uniqueness_
     If the result is an array and the `(u)' flag was present, duplicate
     elements are removed from the array.

19. _Ordering_
     If the result is still an array and one of the `(o)' or `(O)' flags
     was present, the array is reordered.

20. _Re-Evaluation_
     Any `(e)' flag is applied to the value, forcing it to be
     re-examined for new parameter substitutions, but also for command
     and arithmetic substitutions.

21. _Padding_
     Any padding of the value by the `(l.FILL.)' or `(r.FILL.)' flags
     is applied.

22. _Semantic Joining_
     In contexts where expansion semantics requires a single word to
     result, all words are rejoined with the first character of IFS
     between.  So in `${(P)${(f)lines}}' the value of ${lines} is split
     at newlines, but then must be joined again before the P flag can
     be applied.

     If a single word is not required, this rule is skipped.

23. _Empty argument removal_
     If the substitution does not appear in double quotes, any resulting
     zero-length argument, whether from a scalar or an element of an
     array, is elided from the list of arguments inserted into the
     command line.

     Strictly speaking, the removal happens later as the same happens
     with other forms of substitution; the point to note here is simply
     that it occurs after any of the above parameter operations.



14.3.3 Examples
---------------

The flag f is useful to split a double-quoted substitution line by
line.  For example, ${(f)"$(<FILE)"} substitutes the contents of FILE
divided so that each line is an element of the resulting array.
Compare this with the effect of $(<FILE) alone, which divides the file
up by words, or the same inside double quotes, which makes the entire
content of the file a single string.

The following illustrates the rules for nested parameter expansions.
Suppose that $foo contains the array (bar baz):


"${(@)${foo}[1]}"
     This produces the result b.  First, the inner substitution
     "${foo}", which has no array (@) flag, produces a single word
     result "bar baz".  The outer substitution "${(@)...[1]}" detects
     that this is a scalar, so that (despite the `(@)' flag) the
     subscript picks the first character.

"${${(@)foo}[1]}"
     This produces the result `bar'.  In this case, the inner
     substitution "${(@)foo}" produces the array `(bar baz)'.  The outer
     substitution "${...[1]}" detects that this is an array and picks
     the first word.  This is similar to the simple case "${foo[1]}".


As an example of the rules for word splitting and joining, suppose $foo
contains the array `(ax1 bx1)'.  Then


${(s/x/)foo}
     produces the words `a', `1 b' and `1'.

${(j/x/s/x/)foo}
     produces `a', `1', `b' and `1'.

${(s/x/)foo%%1*}
     produces `a' and ` b' (note the extra space).  As substitution
     occurs before either joining or splitting, the operation  first
     generates the modified array (ax bx), which is joined to give "ax
     bx", and then split to give `a', ` b' and `'.  The final empty
     string will then be elided, as it is not in double quotes.



File: zsh.info,  Node: Command Substitution,  Next: Arithmetic Expansion,  Prev: Parameter Expansion,  Up: Expansion

14.4 Command Substitution
=========================

A command enclosed in parentheses preceded by a dollar sign, like
`$(...)', or quoted with grave accents, like ``...`', is replaced with
its standard output, with any trailing newlines deleted.  If the
substitution is not enclosed in double quotes, the output is broken
into words using the IFS parameter.  The substitution `$(cat FOO)' may
be replaced by the equivalent but faster `$(<FOO)'.  In either case, if
the option GLOB_SUBST is set, the output is eligible for filename
generation.

File: zsh.info,  Node: Arithmetic Expansion,  Next: Brace Expansion,  Prev: Command Substitution,  Up: Expansion

14.5 Arithmetic Expansion
=========================

A string of the form `$[EXP]' or `$((EXP))' is substituted with the
value of the arithmetic expression EXP.  EXP is subjected to _parameter
expansion_, _command substitution_ and _arithmetic expansion_ before it
is evaluated.  See *note Arithmetic Evaluation::.

File: zsh.info,  Node: Brace Expansion,  Next: Filename Expansion,  Prev: Arithmetic Expansion,  Up: Expansion

14.6 Brace Expansion
====================

A string of the form `FOO{XX,YY,ZZ}BAR' is expanded to the individual
words `FOOXXBAR', `FOOYYBAR' and `FOOZZBAR'.  Left-to-right order is
preserved.  This construct may be nested.  Commas may be quoted in
order to include them literally in a word.

An expression of the form `{N1..N2}', where N1 and N2 are integers, is
expanded to every number between N1 and N2 inclusive.  If either number
begins with a zero, all the resulting numbers will be padded with
leading zeroes to that minimum width, but for negative numbers the -
character is also included in the width.  If the numbers are in
decreasing order the resulting sequence will also be in decreasing
order.

An expression of the form `{N1..N2..N3}', where N1, N2, and N3 are
integers, is expanded as above, but only every N3th number starting
from N1 is output.  If N3 is negative the numbers are output in reverse
order, this is slightly different from simply swapping N1 and N2 in the
case that the step N3 doesn't evenly divide the range.  Zero padding
can be specified in any of the three numbers, specifying it in the
third can be useful to pad for example `{-99..100..01}' which is not
possible to specify by putting a 0 on either of the first two numbers
(i.e. pad to two characters).

If a brace expression matches none of the above forms, it is left
unchanged, unless the option BRACE_CCL (an abbreviation for `brace
character class') is set.  In that case, it is expanded to a list of
the individual characters between the braces sorted into the order of
the characters in the ASCII character set (multibyte characters are not
currently handled).  The syntax is similar to a [...] expression in
filename generation: `-' is treated specially to denote a range of
characters, but `^' or `!' as the first character is treated normally.
For example, `{abcdef0-9}' expands to 16 words 0 1 2 3 4 5 6 7 8 9 a b
c d e f.

Note that brace expansion is not part of filename generation
(globbing); an expression such as */{foo,bar} is split into two
separate words */foo and */bar before filename generation takes place.
In particular, note that this is liable to produce a `no match' error if
_either_ of the two expressions does not match; this is to be contrasted
with */(foo|bar), which is treated as a single pattern but otherwise
has similar effects.

To combine brace expansion with array expansion, see the ${^SPEC} form
described in *note Parameter Expansion:: above.



File: zsh.info,  Node: Filename Expansion,  Next: Filename Generation,  Prev: Brace Expansion,  Up: Expansion

14.7 Filename Expansion
=======================

Each word is checked to see if it begins with an unquoted `~'.  If it
does, then the word up to a `/', or the end of the word if there is no
`/', is checked to see if it can be substituted in one of the ways
described here.  If so, then the `~' and the checked portion are
replaced with the appropriate substitute value.

A `~' by itself is replaced by the value of $HOME.  A `~' followed by a
`+' or a `-' is replaced by current or previous working directory,
respectively.

A `~' followed by a number is replaced by the directory at that
position in the directory stack.  `~0' is equivalent to `~+', and `~1'
is the top of the stack.  `~+' followed by a number is replaced by the
directory at that position in the directory stack.  `~+0' is equivalent
to `~+', and `~+1' is the top of the stack.  `~-' followed by a number
is replaced by the directory that many positions from the bottom of the
stack.  `~-0' is the bottom of the stack.  The PUSHD_MINUS option
exchanges the effects of `~+' and `~-' where they are followed by a
number.



14.7.1 Dynamic named directories
--------------------------------



The feature described here is only available if the shell function
zsh_directory_name exists.

A `~' followed by a string NAMSTR in unquoted square brackets is
treated specially as a dynamic directory name.  Note that the first
unquoted closing square bracket always terminates NAMSTR.  The shell
function is passed two arguments: the string n (for name) and NAMSTR.
It should either set the array reply to a single element which is the
directory corresponding to the name and return status zero (executing
an assignment as the last statement is usually sufficient), or it
should return status non-zero.  In the former case the element of reply
is used as the directory; in the latter case the substitution is deemed
to have failed and NOMATCH handling is applied if the option is set.

The function zsh_directory_name is also used to see if a directory can
be turned into a name, for example when printing the directory stack or
when expanding %~ in prompts.  In this case the function is passed two
arguments: the string d (for directory) and the candidate for dynamic
naming.  The function should either return non-zero status, if the
directory cannot be named by the function, or it should set the array
reply to consist of two elements: the first is the dynamic name for the
directory (as would appear within `~[...]'), and the second is the
prefix length of the directory to be replaced.  For example, if the
trial directory is /home/myname/src/zsh and the dynamic name for
/home/myname/src (which has 16 characters) is s, then the function sets


     reply=(s 16)

The directory name so returned is compared with possible static names
for parts of the directory path, as described below; it is used if the
prefix length matched (16 in the example) is longer than that matched
by any static name.

The completion system calls `zsh_directory_name c' in order to complete
dynamic names for directories.  The code for this should be as for any
other completion function as described in *note Completion System::.

As a working example, here is a function that expands any dynamic names
beginning with the string p: to directories below /home/pws/perforce.
In this simple case a static name for the directory would be just as
effective.


     zsh_directory_name() {
       emulate -L zsh
       setopt extendedglob
       local -a match mbegin mend
       if [[ $1 = d ]]; then
         # turn the directory into a name
         if [[ $2 = (#b)(/home/pws/perforce/)([^/]##)* ]]; then
           typeset -ga reply
           reply=(p:$match[2] $(( ${#match[1]} + ${#match[2]} )) )
         else
           return 1
         fi
       elif [[ $1 = n ]]; then
         # turn the name into a directory
         [[ $2 != (#b)p:(?*) ]] && return 1
         typeset -ga reply
         reply=(/home/pws/perforce/$match[1])
       elif [[ $1 = c ]]; then
         # complete names
         local expl
         local -a dirs
         dirs=(/home/pws/perforce/*(/:t))
         dirs=(p:${^dirs})
         _wanted dynamic-dirs expl 'dynamic directory' compadd -S\] -a dirs
         return
       else
         return 1
       fi
       return 0
     }


14.7.2 Static named directories
-------------------------------

A `~' followed by anything not already covered consisting of any number
of alphanumeric characters or underscore (`_'), hyphen (`-'), or dot
(`.') is looked up as a named directory, and replaced by the value of
that named directory if found.  Named directories are typically home
directories for users on the system.  They may also be defined if the
text after the `~' is the name of a string shell parameter whose value
begins with a `/'.  Note that trailing slashes will be removed from the
path to the directory (though the original parameter is not modified).

It is also possible to define directory names using the -d option to the
hash builtin.

In certain circumstances (in prompts, for instance), when the shell
prints a path, the path is checked to see if it has a named directory
as its prefix.  If so, then the prefix portion is replaced with a `~'
followed by the name of the directory.  The shortest way of referring
to the directory is used, with ties broken in favour of using a named
directory, except when the directory is / itself.  The parameters $PWD
and $OLDPWD are never abbreviated in this fashion.



14.7.3 `=' expansion
--------------------

If a word begins with an unquoted `=' and the EQUALS option is set, the
remainder of the word is taken as the name of a command.  If a command
exists by that name, the word is replaced by the full pathname of the
command.



14.7.4 Notes
------------

Filename expansion is performed on the right hand side of a parameter
assignment, including those appearing after commands of the typeset
family.  In this case, the right hand side will be treated as a
colon-separated list in the manner of the PATH parameter, so that a `~'
or an `=' following a `:' is eligible for expansion.  All such
behaviour can be disabled by quoting the `~', the `=', or the whole
expression (but not simply the colon); the EQUALS option is also
respected.

If the option MAGIC_EQUAL_SUBST is set, any unquoted shell argument in
the form `IDENTIFIER=EXPRESSION' becomes eligible for file expansion as
described in the previous paragraph.  Quoting the first `=' also
inhibits this.



File: zsh.info,  Node: Filename Generation,  Prev: Filename Expansion,  Up: Expansion

14.8 Filename Generation
========================

If a word contains an unquoted instance of one of the characters `*',
`(', `|', `<', `[', or `?', it is regarded as a pattern for filename
generation, unless the GLOB option is unset.  If the EXTENDED_GLOB
option is set, the `^' and `#' characters also denote a pattern;
otherwise they are not treated specially by the shell.

The word is replaced with a list of sorted filenames that match the
pattern.  If no matching pattern is found, the shell gives an error
message, unless the NULL_GLOB option is set, in which case the word is
deleted; or unless the NOMATCH option is unset, in which case the word
is left unchanged.

In filename generation, the character `/' must be matched explicitly;
also, a `.' must be matched explicitly at the beginning of a pattern or
after a `/', unless the GLOB_DOTS option is set.  No filename
generation pattern matches the files `.' or `..'.  In other instances
of pattern matching, the `/' and `.' are not treated specially.

14.8.1 Glob Operators
---------------------


*
     Matches any string, including the null string.

?
     Matches any character.

[...]
     Matches any of the enclosed characters.  Ranges of characters can
     be specified by separating two characters by a `-'.  A `-' or `]'
     may be matched by including it as the first character in the list.  There
     are also several named classes of characters, in the form
     `[:NAME:]' with the following meanings.  The first set use the
     macros provided by the operating system to test for the given
     character combinations, including any modifications due to local
     language settings, see man page ctype(3):


    [:alnum:]
          The character is alphanumeric

    [:alpha:]
          The character is alphabetic

    [:ascii:]
          The character is 7-bit, i.e. is a single-byte character
          without the top bit set.

    [:blank:]
          The character is either space or tab

    [:cntrl:]
          The character is a control character

    [:digit:]
          The character is a decimal digit

    [:graph:]
          The character is a printable character other than whitespace

    [:lower:]
          The character is a lowercase letter

    [:print:]
          The character is printable

    [:punct:]
          The character is printable but neither alphanumeric nor
          whitespace

    [:space:]
          The character is whitespace

    [:upper:]
          The character is an uppercase letter

    [:xdigit:]
          The character is a hexadecimal digit


     Another set of named classes is handled internally by the shell and
     is not sensitive to the locale:


    [:IDENT:]
          The character is allowed to form part of a shell identifier,
          such as a parameter name

    [:IFS:]
          The character is used as an input field separator, i.e. is
          contained in the IFS parameter

    [:IFSSPACE:]
          The character is an IFS white space character; see the
          documentation for IFS in *note Parameters Used By The Shell::.

    [:WORD:]
          The character is treated as part of a word; this test is
          sensitive to the value of the WORDCHARS parameter


     Note that the square brackets are additional to those enclosing
     the whole set of characters, so to test for a single alphanumeric
     character you need `[[:alnum:]]'.  Named character sets can be
     used alongside other types, e.g. `[[:alpha:]0-9]'.

[^...]
[!...]
     Like [...], except that it matches any character which is not in
     the given set.

<[X]-[Y]>
     Matches any number in the range X to Y, inclusive.  Either of the
     numbers may be omitted to make the range open-ended; hence `<->'
     matches any number.  To match individual digits, the [...] form is
     more efficient.

     Be careful when using other wildcards adjacent to patterns of this
     form; for example, <0-9>* will actually match any number
     whatsoever at the start of the string, since the `<0-9>' will
     match the first digit, and the `*' will match any others.  This is
     a trap for the unwary, but is in fact an inevitable consequence of
     the rule that the longest possible match always succeeds.
     Expressions such as `<0-9>[^[:digit:]]*' can be used instead.

(...)
     Matches the enclosed pattern.  This is used for grouping.  If the
     KSH_GLOB option is set, then a `@', `*', `+', `?' or `!'
     immediately preceding the `(' is treated specially, as detailed
     below. The option SH_GLOB prevents bare parentheses from being
     used in this way, though the KSH_GLOB option is still available.

     Note that grouping cannot extend over multiple directories: it is
     an error to have a `/' within a group (this only applies for
     patterns used in filename generation).  There is one exception:  a
     group of the form (PAT/)# appearing as a complete path segment can
     match a sequence of directories.  For example, foo/(a*/)#bar
     matches foo/bar, foo/any/bar, foo/any/anyother/bar, and so on.

X|Y
     Matches either X or Y.  This operator has lower precedence than
     any other.  The `|' character must be within parentheses, to avoid
     interpretation as a pipeline.

^X
     (Requires EXTENDED_GLOB to be set.)  Matches anything except the
     pattern X.  This has a higher precedence than `/', so `^foo/bar'
     will search directories in `.' except `./foo' for a file named
     `bar'.

X~Y
     (Requires EXTENDED_GLOB to be set.)  Match anything that matches
     the pattern X but does not match Y.  This has lower precedence
     than any operator except `|', so `*/*~foo/bar' will search for all
     files in all directories in `.'  and then exclude `foo/bar' if
     there was such a match.  Multiple patterns can be excluded by
     `FOO~BAR~BAZ'.  In the exclusion pattern (Y), `/' and `.' are not
     treated specially the way they usually are in globbing.

X#
     (Requires EXTENDED_GLOB to be set.)  Matches zero or more
     occurrences of the pattern X.  This operator has high precedence;
     `12#' is equivalent to `1(2#)', rather than `(12)#'.  It is an
     error for an unquoted `#' to follow something which cannot be
     repeated; this includes an empty string, a pattern already
     followed by `##', or parentheses when part of a KSH_GLOB pattern
     (for example, `!(FOO)#' is invalid and must be replaced by
     `*(!(FOO))').

X##
     (Requires EXTENDED_GLOB to be set.)  Matches one or more
     occurrences of the pattern X.  This operator has high precedence;
     `12##' is equivalent to `1(2##)', rather than `(12)##'.  No more
     than two active `#' characters may appear together.  (Note the
     potential clash with glob qualifiers in the form `1(2##)' which
     should therefore be avoided.)


14.8.2 ksh-like Glob Operators
------------------------------

If the KSH_GLOB option is set, the effects of parentheses can be
modified by a preceding `@', `*', `+', `?' or `!'.  This character need
not be unquoted to have special effects, but the `(' must be.


@(...)
     Match the pattern in the parentheses.  (Like `(...)'.)

*(...)
     Match any number of occurrences.  (Like `(...)#'.)

+(...)
     Match at least one occurrence.  (Like `(...)##'.)

?(...)
     Match zero or one occurrence.  (Like `(|...)'.)

!(...)
     Match anything but the expression in parentheses.  (Like
     `(^(...))'.)


14.8.3 Precedence
-----------------

The precedence of the operators given above is (highest) `^', `/', `~',
`|' (lowest); the remaining operators are simply treated from left to
right as part of a string, with `#' and `##' applying to the shortest
possible preceding unit (i.e. a character, `?', `[...]', `<...>', or a
parenthesised expression).  As mentioned above, a `/' used as a
directory separator may not appear inside parentheses, while a `|' must
do so; in patterns used in other contexts than filename generation (for
example, in case statements and tests within `[[...]]'), a `/' is not
special; and `/' is also not special after a `~' appearing outside
parentheses in a filename pattern.

14.8.4 Globbing Flags
---------------------

There are various flags which affect any text to their right up to the
end of the enclosing group or to the end of the pattern; they require
the EXTENDED_GLOB option. All take the form (#X) where X may have one
of the following forms:


i
     Case insensitive:  upper or lower case characters in the pattern
     match upper or lower case characters.

l
     Lower case characters in the pattern match upper or lower case
     characters; upper case characters in the pattern still only match
     upper case characters.

I
     Case sensitive:  locally negates the effect of i or l from that
     point on.

b
     Activate backreferences for parenthesised groups in the pattern;
     this does not work in filename generation.  When a pattern with a
     set of active parentheses is matched, the strings matched by the
     groups are stored in the array $match, the indices of the
     beginning of the matched parentheses in the array $mbegin, and the
     indices of the end in the array $mend, with the first element of
     each array corresponding to the first parenthesised group, and so
     on.  These arrays are not otherwise special to the shell.  The
     indices use the same convention as does parameter substitution, so
     that elements of $mend and $mbegin may be used in subscripts; the
     KSH_ARRAYS option is respected.  Sets of globbing flags are not
     considered parenthesised groups; only the first nine active
     parentheses can be referenced.

     For example,


          foo="a string with a message"
          if [[ $foo = (a|an)' '(#b)(*)' '* ]]; then
            print ${foo[$mbegin[1],$mend[1]]}
          fi

     prints `string with a'.  Note that the first parenthesis is before
     the (#b) and does not create a backreference.

     Backreferences work with all forms of pattern matching other than
     filename generation, but note that when performing matches on an
     entire array, such as ${ARRAY#PATTERN}, or a global substitution,
     such as ${PARAM//PAT/REPL}, only the data for the last match
     remains available.  In the case of global replacements this may
     still be useful.  See the example for the m flag below.

     The numbering of backreferences strictly follows the order of the
     opening parentheses from left to right in the pattern string,
     although sets of parentheses may be nested.  There are special
     rules for parentheses followed by `#' or `##'.  Only the last
     match of the parenthesis is remembered: for example, in `[[ abab =
     (#b)([ab])# ]]', only the final `b' is stored in match[1].  Thus
     extra parentheses may be necessary to match the complete segment:
     for example, use `X((ab|cd)#)Y' to match a whole string of either
     `ab' or `cd' between `X' and `Y', using the value of $match[1]
     rather than $match[2].

     If the match fails none of the parameters is altered, so in some
     cases it may be necessary to initialise them beforehand.  If some
     of the backreferences fail to match -- which happens if they are
     in an alternate branch which fails to match, or if they are
     followed by # and matched zero times -- then the matched string is
     set to the empty string, and the start and end indices are set to
     -1.

     Pattern matching with backreferences is slightly slower than
     without.

B
     Deactivate backreferences, negating the effect of the b flag from
     that point on.

cN,M
     The flag (#cN,M) can be used anywhere that the # or ## operators
     can be used; it cannot be combined with other globbing flags and a
     bad pattern error occurs if it is misplaced.  It is equivalent to
     the form {N,M} in regular expressions.  The previous character or
     group is required to match between N and M times, inclusive.  The
     form (#cN) requires exactly N matches; (#c,M) is equivalent to
     specifying N as 0; (#cN,) specifies that there is no maximum limit
     on the number of matches.

m
     Set references to the match data for the entire string matched;
     this is similar to backreferencing and does not work in filename
     generation.  The flag must be in effect at the end of the pattern,
     i.e. not local to a group. The parameters $MATCH,  $MBEGIN and
     $MEND will be set to the string matched and to the indices of the
     beginning and end of the string, respectively.  This is most
     useful in parameter substitutions, as otherwise the string matched
     is obvious.

     For example,


          arr=(veldt jynx grimps waqf zho buck)
          print ${arr//(#m)[aeiou]/${(U)MATCH}}

     forces all the matches (i.e. all vowels) into uppercase, printing
     `vEldt jynx grImps wAqf zhO bUck'.

     Unlike backreferences, there is no speed penalty for using match
     references, other than the extra substitutions required for the
     replacement strings in cases such as the example shown.

M
     Deactivate the m flag, hence no references to match data will be
     created.

aNUM
     Approximate matching: NUM errors are allowed in the string matched
     by the pattern.  The rules for this are described in the next
     subsection.

s, e
     Unlike the other flags, these have only a local effect, and each
     must appear on its own:  `(#s)' and `(#e)' are the only valid
     forms.  The `(#s)' flag succeeds only at the start of the test
     string, and the `(#e)' flag succeeds only at the end of the test
     string; they correspond to `^' and `$' in standard regular
     expressions.  They are useful for matching path segments in
     patterns other than those in filename generation (where path
     segments are in any case treated separately).  For example,
     `*((#s)|/)test((#e)|/)*' matches a path segment `test' in any of
     the following strings: test, test/at/start, at/end/test,
     in/test/middle.

     Another use is in parameter substitution; for example
     `${array/(#s)A*Z(#e)}' will remove only elements of an array which
     match the complete pattern `A*Z'.  There are other ways of
     performing many operations of this type, however the combination
     of the substitution operations `/' and `//' with the `(#s)' and
     `(#e)' flags provides a single simple and memorable method.

     Note that assertions of the form `(^(#s))' also work, i.e. match
     anywhere except at the start of the string, although this actually
     means `anything except a zero-length portion at the start of the
     string'; you need to use `(""~(#s))' to match a zero-length
     portion of the string not at the start.

q
     A `q' and everything up to the closing parenthesis of the globbing
     flags are ignored by the pattern matching code.  This is intended
     to support the use of glob qualifiers, see below.  The result is
     that the pattern `(#b)(*).c(#q.)' can be used both for globbing
     and for matching against a string.  In the former case, the
     `(#q.)' will be treated as a glob qualifier and the `(#b)' will
     not be useful, while in the latter case the `(#b)' is useful for
     backreferences and the `(#q.)' will be ignored.  Note that colon
     modifiers in the glob qualifiers are also not applied in ordinary
     pattern matching.

u
     Respect the current locale in determining the presence of multibyte
     characters in a pattern, provided the shell was compiled with
     MULTIBYTE_SUPPORT.  This overrides the MULTIBYTE option; the
     default behaviour is taken from the option.  Compare U.
     (Mnemonic: typically multibyte characters are from Unicode in the
     UTF-8 encoding, although any extension of ASCII supported by the
     system library may be used.)

U
     All characters are considered to be a single byte long.  The
     opposite of u.  This overrides the MULTIBYTE option.


For example, the test string fooxx can be matched by the pattern
(#i)FOOXX, but not by (#l)FOOXX, (#i)FOO(#I)XX or ((#i)FOOX)X.  The
string (#ia2)readme specifies case-insensitive matching of readme with
up to two errors.

When using the ksh syntax for grouping both KSH_GLOB and EXTENDED_GLOB
must be set and the left parenthesis should be preceded by @.  Note
also that the flags do not affect letters inside [...] groups, in other
words (#i)[a-z] still matches only lowercase letters.  Finally, note
that when examining whole paths case-insensitively every directory must
be searched for all files which match, so that a pattern of the form
(#i)/foo/bar/... is potentially slow.



14.8.5 Approximate Matching
---------------------------

When matching approximately, the shell keeps a count of the errors
found, which cannot exceed the number specified in the (#aNUM) flags.
Four types of error are recognised:


1.
     Different characters, as in fooxbar and fooybar.

2.
     Transposition of characters, as in banana and abnana.

3.
     A character missing in the target string, as with the pattern road
     and target string rod.

4.
     An extra character appearing in the target string, as with stove
     and strove.


Thus, the pattern (#a3)abcd matches dcba, with the errors occurring by
using the first rule twice and the second once, grouping the string as
[d][cb][a] and [a][bc][d].

Non-literal parts of the pattern must match exactly, including
characters in character ranges: hence (#a1)???  matches strings of
length four, by applying rule 4 to an empty part of the pattern, but not
strings of length two, since all the ? must match.  Other characters
which must match exactly are initial dots in filenames (unless the
GLOB_DOTS option is set), and all slashes in filenames, so that a/bc is
two errors from ab/c (the slash cannot be transposed with another
character).  Similarly, errors are counted separately for
non-contiguous strings in the pattern, so that (ab|cd)ef is two errors
from aebf.

When using exclusion via the ~ operator, approximate matching is
treated entirely separately for the excluded part and must be activated
separately.  Thus, (#a1)README~READ_ME matches READ.ME but not READ_ME,
as the trailing READ_ME is matched without approximation.  However,
(#a1)README~(#a1)READ_ME does not match any pattern of the form READ?ME
as all such forms are now excluded.

Apart from exclusions, there is only one overall error count; however,
the maximum errors allowed may be altered locally, and this can be
delimited by grouping.  For example, (#a1)cat((#a0)dog)fox allows one
error in total, which may not occur in the dog section, and the pattern
(#a1)cat(#a0)dog(#a1)fox is equivalent.  Note that the point at which
an error is first found is the crucial one for establishing whether to
use approximation; for example, (#a1)abc(#a0)xyz will not match
abcdxyz, because the error occurs at the `x', where approximation is
turned off.

Entire path segments may be matched approximately, so that
`(#a1)/foo/d/is/available/at/the/bar' allows one error in any path
segment.  This is much less efficient than without the (#a1), however,
since every directory in the path must be scanned for a possible
approximate match.  It is best to place the (#a1) after any path
segments which are known to be correct.



14.8.6 Recursive Globbing
-------------------------

A pathname component of the form `(FOO/)#' matches a path consisting of
zero or more directories matching the pattern FOO.

As a shorthand, `**/' is equivalent to `(*/)#'; note that this
therefore matches files in the current directory as well as
subdirectories.  Thus:


     ls (*/)#bar

or


     ls **/bar

does a recursive directory search for files named `bar' (potentially
including the file `bar' in the current directory).  This form does not
follow symbolic links; the alternative form `***/' does, but is
otherwise identical.  Neither of these can be combined with other forms
of globbing within the same path segment; in that case, the `*'
operators revert to their usual effect.

14.8.7 Glob Qualifiers
----------------------

Patterns used for filename generation may end in a list of qualifiers
enclosed in parentheses.  The qualifiers specify which filenames that
otherwise match the given pattern will be inserted in the argument list.

If the option BARE_GLOB_QUAL is set, then a trailing set of parentheses
containing no `|' or `(' characters (or `~' if it is special) is taken
as a set of glob qualifiers.  A glob subexpression that would normally
be taken as glob qualifiers, for example `(^x)', can be forced to be
treated as part of the glob pattern by doubling the parentheses, in
this case producing `((^x))'.

If the option EXTENDED_GLOB is set, a different syntax for glob
qualifiers is available, namely `(#qx)' where x is any of the same glob
qualifiers used in the other format.  The qualifiers must still appear
at the end of the pattern.  However, with this syntax multiple glob
qualifiers may be chained together.  They are treated as a logical AND
of the individual sets of flags.  Also, as the syntax is unambiguous,
the expression will be treated as glob qualifiers just as long any
parentheses contained within it are balanced; appearance of `|', `(' or
`~' does not negate the effect.  Note that qualifiers will be
recognised in this form even if a bare glob qualifier exists at the end
of the pattern, for example `*(#q*)(.)' will recognise executable
regular files if both options are set; however, mixed syntax should
probably be avoided for the sake of clarity.

A qualifier may be any one of the following:


/
     directories

F
     `full' (i.e. non-empty) directories.  Note that the opposite sense
     (^F) expands to empty directories and all non-directories.  Use
     (/^F) for empty directories.

.
     plain files

@
     symbolic links

=
     sockets

p
     named pipes (FIFOs)

*
     executable plain files (0100)

%
     device files (character or block special)

%b
     block special files

%c
     character special files

r
     owner-readable files (0400)

w
     owner-writable files (0200)

x
     owner-executable files (0100)

A
     group-readable files (0040)

I
     group-writable files (0020)

E
     group-executable files (0010)

R
     world-readable files (0004)

W
     world-writable files (0002)

X
     world-executable files (0001)

s
     setuid files (04000)

S
     setgid files (02000)

t
     files with the sticky bit (01000)

fSPEC
     files with access rights matching SPEC. This SPEC may be a octal
     number optionally preceded by a `=', a `+', or a `-'. If none of
     these characters is given, the behavior is the same as for `='.
     The octal number describes the mode bits to be expected, if
     combined with a `=', the value given must match the file-modes
     exactly, with a `+', at least the bits in the given number must be
     set in the file-modes, and with a `-', the bits in the number must
     not be set. Giving a `?' instead of a octal digit anywhere in the
     number ensures that the corresponding bits in the file-modes are
     not checked, this is only useful in combination with `='.

     If the qualifier `f' is followed by any other character anything
     up to the next matching character (`[', `{', and `<' match `]',
     `}', and `>' respectively, any other character matches itself) is
     taken as a list of comma-separated SUB-SPECs. Each SUB-SPEC may be
     either an octal number as described above or a list of any of the
     characters `u', `g', `o', and `a', followed by a `=', a `+', or a
     `-', followed by a list of any of the characters `r', `w', `x',
     `s', and `t', or an octal digit. The first list of characters
     specify which access rights are to be checked. If a `u' is given,
     those for the owner of the file are used, if a `g' is given, those
     of the group are checked, a `o' means to test those of other
     users, and the `a' says to test all three groups. The `=', `+',
     and `-' again says how the modes are to be checked and have the
     same meaning as described for the first form above. The second
     list of characters finally says which access rights are to be
     expected: `r' for read access, `w' for write access, `x' for the
     right to execute the file (or to search a directory), `s' for the
     setuid and setgid bits, and `t' for the sticky bit.

     Thus, `*(f70?)' gives the files for which the owner has read,
     write, and execute permission, and for which other group members
     have no rights, independent of the permissions for other users.
     The pattern `*(f-100)' gives all files for which the owner does
     not have execute permission, and `*(f:gu+w,o-rx:)' gives the files
     for which the owner and the other members of the group have at
     least write permission, and for which other users don't have read
     or execute permission.

eSTRING
+CMD
     The STRING will be executed as shell code.  The filename will be
     included in the list if and only if the code returns a zero status
     (usually the status of the last command).

     In the first form, the first character after the `e' will be used
     as a separator and anything up to the next matching separator will
     be taken  as the STRING; `[', `{', and `<' match `]', `}', and
     `>', respectively, while any other character matches itself. Note
     that expansions must be quoted in the STRING to prevent them from
     being expanded before globbing is done.  STRING is then executed
     as shell code.  The string globqual is appended to the array
     zsh_eval_context the duration of execution.

     During the execution of STRING the filename currently being tested
     is available in the parameter REPLY; the parameter may be altered
     to a string to be inserted into the list instead of the original
     filename.  In addition, the parameter reply may be set to an array
     or a string, which overrides the value of REPLY.  If set to an
     array, the latter is inserted into the command line word by word.

     For example, suppose a directory contains a single file `lonely'.
     Then the expression `*(e:'reply=(${REPLY}{1,2})':)' will cause the
     words `lonely1 lonely2' to be inserted into the command line.
     Note the quotation marks.

     The form +CMD has the same effect, but no delimiters appear around
     CMD.  Instead, CMD is taken as the longest sequence of characters
     following the + that are alphanumeric or underscore.  Typically
     CMD will be the name of a shell function that contains the
     appropriate test.  For example,


          nt() { [[ $REPLY -nt $NTREF ]] }
          NTREF=reffile
          ls -l *(+nt)

     lists all files in the directory that have been modified more
     recently than reffile.

dDEV
     files on the device DEV

l[-|+]CT
     files having a link count less than CT (-), greater than CT (+),
     or equal to CT

U
     files owned by the effective user ID

G
     files owned by the effective group ID

uID
     files owned by user ID ID if that is a number.  Otherwise, ID
     specifies a user name: the character after the `u' will be taken
     as a separator and the string between it and the next matching
     separator will be taken as a user name.  The starting separators
     `[', `{', and `<' match the final separators `]', `}', and `>',
     respectively; any other character matches itself.  The selected
     files are those owned by this user.  For example, `u:foo:' or
     `u[foo]' selects files owned by user `foo'.

gID
     like uID but with group IDs or names

a[Mwhms][-|+]N
     files accessed exactly N days ago.  Files accessed within the last
     N days are selected using a negative value for N (-N).  Files
     accessed more than N days ago are selected by a positive N value
     (+N).  Optional unit specifiers `M', `w', `h', `m' or `s' (e.g.
     `ah5') cause the check to be performed with months (of 30 days),
     weeks, hours, minutes or seconds instead of days, respectively.

     Any fractional part of the difference between the access time and
     the current part in the appropriate units is ignored in the
     comparison.  For instance, `echo *(ah-5)' would echo files
     accessed within the last five hours, while `echo *(ah+5)' would
     echo files accessed at least six hours ago, as times strictly
     between five and six hours are treated as five hours.

m[Mwhms][-|+]N
     like the file access qualifier, except that it uses the file
     modification time.

c[Mwhms][-|+]N
     like the file access qualifier, except that it uses the file inode
     change time.

L[+|-]N
     files less than N bytes (-), more than N bytes (+), or exactly N
     bytes in length.

     If this flag is directly followed by a `k' (`K'), `m' (`M'), or
     `p' (`P') (e.g. `Lk-50') the check is performed with kilobytes,
     megabytes, or blocks (of 512 bytes) instead.  In this case a file
     is regarded as "exactly" the size if the file size rounded up to
     the next unit is equal to the test size.  Hence `*(Lm1)' matches
     files from 1 byte up to 1 Megabyte inclusive.  Note also that the
     set of files "less than" the test size only includes files that
     would not match the equality test; hence `*(Lm-1)' only matches
     files of zero size.

^
     negates all qualifiers following it

-
     toggles between making the qualifiers work on symbolic links (the
     default) and the files they point to

M
     sets the MARK_DIRS option for the current pattern

T
     appends a trailing qualifier mark to the filenames, analogous to
     the LIST_TYPES option, for the current pattern (overrides M)

N
     sets the NULL_GLOB option for the current pattern

D
     sets the GLOB_DOTS option for the current pattern

n
     sets the NUMERIC_GLOB_SORT option for the current pattern

oC
     specifies how the names of the files should be sorted. If C is n
     they are sorted by name (the default); if it is L they are sorted
     depending on the size (length) of the files; if l they are sorted
     by the number of links; if a, m, or c they are sorted by the time
     of the last access, modification, or inode change respectively; if
     d, files in subdirectories appear before those in the current
     directory at each level of the search -- this is best combined
     with other criteria, for example `odon' to sort on names for files
     within the same directory; if N, no sorting is performed.  Note
     that a, m, and c compare the age against the current time, hence
     the first name in the list is the youngest file. Also note that
     the modifiers ^ and - are used, so `*(^-oL)' gives a list of all
     files sorted by file size in descending order, following any
     symbolic links.  Unless oN is used, multiple order specifiers may
     occur to resolve ties.

     oe and o+ are special cases; they are each followed by shell code,
     delimited as for the e glob qualifier and the + glob qualifier
     respectively (see above).  The code is executed for each matched
     file with the parameter REPLY set to the name of the file on entry
     and globsort appended to zsh_eval_context.  The code should modify
     the parameter REPLY in some fashion.  On return, the value of the
     parameter is used instead of the file name as the string on which
     to sort.  Unlike other sort operators, oe and o+ may be repeated,
     but note that the maximum number of sort operators of any kind
     that may appear in any glob expression is 12.

OC
     like `o', but sorts in descending order; i.e. `*(^oc)' is the same
     as `*(Oc)' and `*(^Oc)' is the same as `*(oc)'; `Od' puts files in
     the current directory before those in subdirectories at each level
     of the search.

[BEG[,END]]
     specifies which of the matched filenames should be included in the
     returned list. The syntax is the same as for array subscripts. BEG
     and the optional END may be mathematical expressions. As in
     parameter subscripting they may be negative to make them count
     from the last match backward. E.g.: `*(-OL[1,3])' gives a list of
     the names of the three largest files.

PSTRING
     The STRING will be prepended to each glob match as a separate
     word.  STRING is delimited in the same way as arguments to the e
     glob qualifier described above.  The qualifier can be repeated;
     the words are prepended separately so that the resulting command
     line contains the words in the same order they were given in the
     list of glob qualifiers.

     A typical use for this is to prepend an option before all
     occurrences of a file name; for example, the pattern `*(P:-f:)'
     produces the command line arguments `-f FILE1 -f FILE2 ...'


More than one of these lists can be combined, separated by commas. The
whole list matches if at least one of the sublists matches (they are
`or'ed, the qualifiers in the sublists are `and'ed).  Some qualifiers,
however, affect all matches generated, independent of the sublist in
which they are given.  These are the qualifiers `M', `T', `N', `D',
`n', `o', `O' and the subscripts given in brackets (`[...]').

If a `:' appears in a qualifier list, the remainder of the expression in
parenthesis is interpreted as a modifier (see *note Modifiers:: in
*note History Expansion::).  Each modifier must be introduced by a
separate `:'.  Note also that the result after modification does not
have to be an existing file.  The name of any existing file can be
followed by a modifier of the form `(:..)' even if no actual filename
generation is performed, although note that the presence of the
parentheses causes the entire expression to be subjected to any global
pattern matching options such as NULL_GLOB. Thus:


     ls *(-/)

lists all directories and symbolic links that point to directories, and


     ls *(%W)

lists all world-writable device files in the current directory, and


     ls *(W,X)

lists all files in the current directory that are world-writable or
world-executable, and


     echo /tmp/foo*(u0^@:t)

outputs the basename of all root-owned files beginning with the string
`foo' in /tmp, ignoring symlinks, and


     ls *.*~(lex|parse).[ch](^D^l1)

lists all files having a link count of one whose names contain a dot
(but not those starting with a dot, since GLOB_DOTS is explicitly
switched off) except for lex.c, lex.h, parse.c and parse.h.


     print b*.pro(#q:s/pro/shmo/)(#q.:s/builtin/shmiltin/)

demonstrates how colon modifiers and other qualifiers may be chained
together.  The ordinary qualifier `.' is applied first, then the colon
modifiers in order from left to right.  So if EXTENDED_GLOB is set and
the base pattern matches the regular file builtin.pro, the shell will
print `shmiltin.shmo'.

File: zsh.info,  Node: Parameters,  Next: Options,  Prev: Expansion,  Up: Top

15 Parameters
*************



15.1 Description
================

A parameter has a name, a value, and a number of attributes.  A name
may be any sequence of alphanumeric characters and underscores, or the
single characters `*', `@', `#', `?', `-', `$', or `!'.  The value may
be a _scalar_ (a string), an integer, an array (indexed numerically),
or an _associative_ array (an unordered set of name-value pairs,
indexed by name).  To declare the type of a parameter, or to assign a
scalar or integer value to a parameter, use the typeset builtin.

The value of a scalar or integer parameter may also be assigned by
writing:



     NAME=VALUE

If the integer attribute, -i, is set for NAME, the VALUE is subject to
arithmetic evaluation.  Furthermore, by replacing `=' with `+=', a
parameter can be added or appended to.  See *note Array Parameters::
for additional forms of assignment.

To refer to the value of a parameter, write `$NAME' or `${NAME}'.  See
*note Parameter Expansion:: for complete details.

In the parameter lists that follow, the mark `<S>' indicates that the
parameter is special.  Special parameters cannot have their type
changed or their readonly attribute turned off, and if a special
parameter is unset, then later recreated, the special properties will
be retained.  `<Z>' indicates that the parameter does not exist when
the shell initializes in sh or ksh emulation mode.

* Menu:

* Array Parameters::
* Positional Parameters::
* Local Parameters::
* Parameters Set By The Shell::
* Parameters Used By The Shell::

File: zsh.info,  Node: Array Parameters,  Next: Positional Parameters,  Up: Parameters

15.2 Array Parameters
=====================

To assign an array value, write one of:



     set -A NAME VALUE ...

     NAME=(VALUE ...)

If no parameter NAME exists, an ordinary array parameter is created.
If the parameter NAME exists and is a scalar, it is replaced by a new
array.  Ordinary array parameters may also be explicitly declared with:



     typeset -a NAME

Associative arrays _must_ be declared before assignment, by using:



     typeset -A NAME

When NAME refers to an associative array, the list in an assignment is
interpreted as alternating keys and values:



     set -A NAME KEY VALUE ...

     NAME=(KEY VALUE ...)

Every KEY must have a VALUE in this case.  Note that this assigns to
the entire array, deleting any elements that do not appear in the list.

To create an empty array (including associative arrays), use one of:



     set -A NAME

     NAME=()


15.2.1 Array Subscripts
-----------------------



Individual elements of an array may be selected using a subscript.  A
subscript of the form `[EXP]' selects the single element EXP, where EXP
is an arithmetic expression which will be subject to arithmetic
expansion as if it were surrounded by `$((...))'.  The elements are
numbered beginning with 1, unless the KSH_ARRAYS option is set in which
case they are numbered from zero.

Subscripts may be used inside braces used to delimit a parameter name,
thus `${foo[2]}' is equivalent to `$foo[2]'.  If the KSH_ARRAYS option
is set, the braced form is the only one that works, as bracketed
expressions otherwise are not treated as subscripts.

If the KSH_ARRAYS option is not set, then by default accesses to an
array element with a subscript that evaluates to zero return an empty
string, while an attempt to write such an element is treated as an
error.  For backward compatibility the KSH_ZERO_SUBSCRIPT option can be
set to cause subscript values 0 and 1 to be equivalent; see the
description of the option in *note Description of Options::.

The same subscripting syntax is used for associative arrays, except that
no arithmetic expansion is applied to EXP.  However, the parsing rules
for arithmetic expressions still apply, which affects the way that
certain special characters must be protected from interpretation.  See
_Subscript Parsing_ below for details.

A subscript of the form `[*]' or `[@]' evaluates to all elements of an
array; there is no difference between the two except when they appear
within double quotes.  `"$foo[*]"' evaluates to `"$foo[1] $foo[2]
..."', whereas `"$foo[@]"' evaluates to `"$foo[1]" "$foo[2]" ...'.  For
associative arrays, `[*]' or `[@]' evaluate to all the values, in no
particular order.  Note that this does not substitute the keys; see the
documentation for the `k' flag under *note Parameter Expansion:: for
complete details.  When an array parameter is referenced as `$NAME'
(with no subscript) it evaluates to `$NAME[*]', unless the KSH_ARRAYS
option is set in which case it evaluates to `${NAME[0]}' (for an
associative array, this means the value of the key `0', which may not
exist even if there are values for other keys).

A subscript of the form `[EXP1,EXP2]' selects all elements in the range
EXP1 to EXP2, inclusive. (Associative arrays are unordered, and so do
not support ranges.) If one of the subscripts evaluates to a negative
number, say -N, then the Nth element from the end of the array is used.
Thus `$foo[-3]' is the third element from the end of the array foo, and
`$foo[1,-1]' is the same as `$foo[*]'.

Subscripting may also be performed on non-array values, in which case
the subscripts specify a substring to be extracted.  For example, if
FOO is set to `foobar', then `echo $FOO[2,5]' prints `ooba'.



15.2.2 Array Element Assignment
-------------------------------

A subscript may be used on the left side of an assignment like so:



     NAME[EXP]=VALUE

In this form of assignment the element or range specified by EXP is
replaced by the expression on the right side.  An array (but not an
associative array) may be created by assignment to a range or element.
Arrays do not nest, so assigning a parenthesized list of values to an
element or range changes the number of elements in the array, shifting
the other elements to accommodate the new values.  (This is not
supported for associative arrays.)

This syntax also works as an argument to the typeset command:



     typeset "NAME[EXP]"=VALUE

The VALUE may _not_ be a parenthesized list in this case; only
single-element assignments may be made with typeset.  Note that quotes
are necessary in this case to prevent the brackets from being
interpreted as filename generation operators.  The noglob precommand
modifier could be used instead.

To delete an element of an ordinary array, assign `()' to that element.
To delete an element of an associative array, use the unset command:



     unset "NAME[EXP]"


15.2.3 Subscript Flags
----------------------



If the opening bracket, or the comma in a range, in any subscript
expression is directly followed by an opening parenthesis, the string up
to the matching closing one is considered to be a list of flags, as in
`NAME[(FLAGS)EXP]'.

The flags s, n and b take an argument; the delimiter is shown below as
`:', but any character, or the matching pairs `(...)', `{...}',
`[...]', or `<...>', may be used.

The flags currently understood are:


w
     If the parameter subscripted is a scalar then this flag makes
     subscripting work on words instead of characters.  The default word
     separator is whitespace.  This flag may not be used with the i or
     I flag.

s:STRING:
     This gives the STRING that separates words (for use with the w
     flag).  The delimiter character : is arbitrary; see above.

p
     Recognize the same escape sequences as the print builtin in the
     string argument of a subsequent `s' flag.

f
     If the parameter subscripted is a scalar then this flag makes
     subscripting work on lines instead of characters, i.e. with
     elements separated by newlines.  This is a shorthand for `pws:\n:'.

r
     Reverse subscripting: if this flag is given, the EXP is taken as a
     pattern and the result is the first matching array element,
     substring or word (if the parameter is an array, if it is a
     scalar, or if it is a scalar and the `w' flag is given,
     respectively).  The subscript used is the number of the matching
     element, so that pairs of subscripts such as `$foo[(r)??,3]' and
     `$foo[(r)??,(r)f*]' are possible if the parameter is not an
     associative array.  If the parameter is an associative array, only
     the value part of each pair is compared to the pattern, and the
     result is that value.

     If a search through an ordinary array failed, the search sets the
     subscript to one past the end of the array, and hence
     ${array[(r)pattern]} will substitute the empty string.  Thus the
     success of a search can be tested by using the (i) flag, for
     example (assuming the option KSH_ARRAYS is not in effect):


          [[ ${array[(i)pattern]} -le ${#array} ]]

     If KSH_ARRAYS is in effect, the -le should be replaced by -lt.

R
     Like `r', but gives the last match.  For associative arrays, gives
     all possible matches. May be used for assigning to ordinary array
     elements, but not for assigning to associative arrays.  On
     failure, for normal arrays this has the effect of returning the
     element corresponding to subscript 0; this is empty unless one of
     the options KSH_ARRAYS or KSH_ZERO_SUBSCRIPT is in effect.

     Note that in subscripts with both `r' and `R' pattern characters
     are active even if they were substituted for a parameter
     (regardless of the setting of GLOB_SUBST which controls this
     feature in normal pattern matching).  The flag `e' can be added to
     inhibit pattern matching.  As this flag does not inhibit other
     forms of substitution, care is still required; using a parameter
     to hold the key has the desired effect:


          key2='original key'
          print ${array[(Re)$key2]}

i
     Like `r', but gives the index of the match instead; this may not be
     combined with a second argument.  On the left side of an
     assignment, behaves like `r'.  For associative arrays, the key
     part of each pair is compared to the pattern, and the first
     matching key found is the result.  On failure substitutes the
     length of the array plus one, as discussed under the description
     of `r', or the empty string for an associative array.

I
     Like `i', but gives the index of the last match, or all possible
     matching keys in an associative array.  On failure substitutes 0,
     or the empty string for an associative array.  This flag is best
     when testing for values or keys that do not exist.

k
     If used in a subscript on an associative array, this flag causes
     the keys to be interpreted as patterns, and returns the value for
     the first key found where EXP is matched by the key.  Note this
     could be any such key as no ordering of associative arrays is
     defined.  This flag does not work on the left side of an
     assignment to an associative array element.  If used on another
     type of parameter, this behaves like `r'.

K
     On an associative array this is like `k' but returns all values
     where EXP is matched by the keys.  On other types of parameters
     this has the same effect as `R'.

n:EXPR:
     If combined with `r', `R', `i' or `I', makes them give the Nth or
     Nth last match (if EXPR evaluates to N).  This flag is ignored
     when the array is associative.  The delimiter character : is
     arbitrary; see above.

b:EXPR:
     If combined with `r', `R', `i' or `I', makes them begin at the Nth
     or Nth last element, word, or character (if EXPR evaluates to N).
     This flag is ignored when the array is associative.  The delimiter
     character : is arbitrary; see above.

e
     This flag causes any pattern matching that would be performed on
     the subscript to use plain string matching instead.  Hence
     `${array[(re)*]}' matches only the array element whose value is *.
     Note that other forms of substitution such as parameter
     substitution are not inhibited.

     This flag can also be used to force * or @ to be interpreted as a
     single key rather than as a reference to all values.  It may be
     used for either purpose on the left side of an assignment.


See _Parameter Expansion Flags_ (*note Parameter Expansion::) for
additional ways to manipulate the results of array subscripting.



15.2.4 Subscript Parsing
------------------------

This discussion applies mainly to associative array key strings and to
patterns used for reverse subscripting (the `r', `R', `i', etc. flags),
but it may also affect parameter substitutions that appear as part of
an arithmetic expression in an ordinary subscript.

It is possible to avoid the use of subscripts in assignments to
associative array elements by using the syntax:



        aa+=('key with "*strange*" characters' 'value string')

This adds a new key/value pair if the key is not already present, and
replaces the value for the existing key if it is.

The basic rule to remember when writing a subscript expression is that
all text between the opening `[' and the closing `]' is interpreted _as
if_ it were in double quotes (*note Quoting::).  However, unlike double
quotes which normally cannot nest, subscript expressions may appear
inside double-quoted strings or inside other subscript expressions (or
both!), so the rules have two important differences.

The first difference is that brackets (`[' and `]') must appear as
balanced pairs in a subscript expression unless they are preceded by a
backslash (`\').  Therefore, within a subscript expression (and unlike
true double-quoting) the sequence `\[' becomes `[', and similarly `\]'
becomes `]'.  This applies even in cases where a backslash is not
normally required; for example, the pattern `[^[]' (to match any
character other than an open bracket) should be written `[^\[]' in a
reverse-subscript pattern.  However, note that `\[^\[\]' and even
`\[^[]' mean the _same_ thing, because backslashes are always stripped
when they appear before brackets!

The same rule applies to parentheses (`(' and `)') and braces (`{' and
`}'): they must appear either in balanced pairs or preceded by a
backslash, and backslashes that protect parentheses or braces are
removed during parsing.  This is because parameter expansions may be
surrounded by balanced braces, and subscript flags are introduced by
balanced parentheses.

The second difference is that a double-quote (`"') may appear as part
of a subscript expression without being preceded by a backslash, and
therefore that the two characters `\"' remain as two characters in the
subscript (in true double-quoting, `\"' becomes `"').  However, because
of the standard shell quoting rules, any double-quotes that appear must
occur in balanced pairs unless preceded by a backslash.  This makes it
more difficult to write a subscript expression that contains an odd
number of double-quote characters, but the reason for this difference is
so that when a subscript expression appears inside true double-quotes,
one can still write `\"' (rather than `\\\"') for `"'.

To use an odd number of double quotes as a key in an assignment, use the
typeset builtin and an enclosing pair of double quotes; to refer to the
value of that key, again use double quotes:


     typeset -A aa
     typeset "aa[one\"two\"three\"quotes]"=QQQ
     print "$aa[one\"two\"three\"quotes]"

It is important to note that the quoting rules do not change when a
parameter expansion with a subscript is nested inside another subscript
expression.  That is, it is not necessary to use additional backslashes
within the inner subscript expression; they are removed only once, from
the innermost subscript outwards.  Parameters are also expanded from the
innermost subscript first, as each expansion is encountered left to
right in the outer expression.

A further complication arises from a way in which subscript parsing is
_not_ different from double quote parsing.  As in true double-quoting,
the sequences `\*', and `\@' remain as two characters when they appear
in a subscript expression.  To use a literal `*' or `@' as an
associative array key, the `e' flag must be used:


     typeset -A aa
     aa[(e)*]=star
     print $aa[(e)*]

A last detail must be considered when reverse subscripting is performed.
Parameters appearing in the subscript expression are first expanded and
then the complete expression is interpreted as a pattern.  This has two
effects: first, parameters behave as if GLOB_SUBST were on (and it
cannot be turned off); second, backslashes are interpreted twice, once
when parsing the array subscript and again when parsing the pattern.
In a reverse subscript, it's necessary to use _four_ backslashes to
cause a single backslash to match literally in the pattern.  For
complex patterns, it is often easiest to assign the desired pattern to
a parameter and then refer to that parameter in the subscript, because
then the backslashes, brackets, parentheses, etc., are seen only when
the complete expression is converted to a pattern.  To match the value
of a parameter literally in a reverse subscript, rather than as a
pattern, use `${(q)NAME}' (*note Parameter Expansion::) to quote the
expanded value.

Note that the `k' and `K' flags are reverse subscripting for an
ordinary array, but are _not_ reverse subscripting for an associative
array!  (For an associative array, the keys in the array itself are
interpreted as patterns by those flags; the subscript is a plain string
in that case.)

One final note, not directly related to subscripting: the numeric names
of positional parameters (*note Positional Parameters::) are parsed
specially, so for example `$2foo' is equivalent to `${2}foo'.
Therefore, to use subscript syntax to extract a substring from a
positional parameter, the expansion must be surrounded by braces; for
example, `${2[3,5]}' evaluates to the third through fifth characters of
the second positional parameter, but `$2[3,5]' is the entire second
parameter concatenated with the filename generation pattern `[3,5]'.



File: zsh.info,  Node: Positional Parameters,  Next: Local Parameters,  Prev: Array Parameters,  Up: Parameters

15.3 Positional Parameters
==========================

The positional parameters provide access to the command-line arguments
of a shell function, shell script, or the shell itself; see *note
Invocation::, and also *note Functions::.  The parameter N, where N is
a number, is the Nth positional parameter.  The parameters *, @ and
argv are arrays containing all the positional parameters; thus
`$argv[N]', etc., is equivalent to simply `$N'.

Positional parameters may be changed after the shell or function starts
by using the set builtin, by assigning to the argv array, or by direct
assignment of the form `N=VALUE' where N is the number of the
positional parameter to be changed.  This also creates (with empty
values) any of the positions from 1 to N that do not already have
values.  Note that, because the positional parameters form an array, an
array assignment of the form `N=(VALUE ...)' is allowed, and has the
effect of shifting all the values at positions greater than N by as
many positions as necessary to accommodate the new values.



File: zsh.info,  Node: Local Parameters,  Next: Parameters Set By The Shell,  Prev: Positional Parameters,  Up: Parameters

15.4 Local Parameters
=====================

Shell function executions delimit scopes for shell parameters.
(Parameters are dynamically scoped.)  The typeset builtin, and its
alternative forms declare, integer, local and readonly (but not
export), can be used to declare a parameter as being local to the
innermost scope.

When a parameter is read or assigned to, the innermost existing
parameter of that name is used.  (That is, the local parameter hides
any less-local parameter.)  However, assigning to a non-existent
parameter, or declaring a new parameter with export, causes it to be
created in the _outer_most scope.

Local parameters disappear when their scope ends.  unset can be used to
delete a parameter while it is still in scope; any outer parameter of
the same name remains hidden.

Special parameters may also be made local; they retain their special
attributes unless either the existing or the newly-created parameter
has the -h (hide) attribute.  This may have unexpected effects: there
is no default value, so if there is no assignment at the point the
variable is made local, it will be set to an empty value (or zero in
the case of integers).  The following:


     typeset PATH=/new/directory:$PATH

is valid for temporarily allowing the shell or programmes called from
it to find the programs in /new/directory inside a function.

Note that the restriction in older versions of zsh that local parameters
were never exported has been removed.



File: zsh.info,  Node: Parameters Set By The Shell,  Next: Parameters Used By The Shell,  Prev: Local Parameters,  Up: Parameters

15.5 Parameters Set By The Shell
================================

The following parameters are automatically set by the shell:


! <S>
     The process ID of the last command started in the background with
     &, or put into the background with the bg builtin.

# <S>
     The number of positional parameters in decimal.  Note that some
     confusion may occur with the syntax $#PARAM which substitutes the
     length of PARAM.  Use ${#} to resolve ambiguities.  In particular,
     the sequence `$#-...' in an arithmetic expression is interpreted as
     the length of the parameter -, q.v.

ARGC <S> <Z>
     Same as #.

$ <S>
     The process ID of this shell.  Note that this indicates the
     original shell started by invoking zsh; all processes forked from
     the shells without executing a new program, such as subshells
     started by (...), substitute the same value.

- <S>
     Flags supplied to the shell on invocation or by the set or setopt
     commands.

* <S>
     An array containing the positional parameters.

argv <S> <Z>
     Same as *.  Assigning to argv changes the local positional
     parameters, but argv is _not_ itself a local parameter.  Deleting
     argv with unset in any function deletes it everywhere, although
     only the innermost positional parameter array is deleted (so * and
     @ in other scopes are not affected).

@ <S>
     Same as argv[@], even when argv is not set.

? <S>
     The exit status returned by the last command.

0 <S>
     The name used to invoke the current shell.  If the
     FUNCTION_ARGZERO option is set, this is set temporarily within a
     shell function to the name of the function, and within a sourced
     script to the name of the script.

status <S> <Z>
     Same as ?.

pipestatus <S> <Z>
     An array containing the exit statuses returned by all commands in
     the last pipeline.

_ <S>
     The last argument of the previous command.  Also, this parameter
     is set in the environment of every command executed to the full
     pathname of the command.

CPUTYPE
     The machine type (microprocessor class or machine model), as
     determined at run time.

EGID <S>
     The effective group ID of the shell process.  If you have
     sufficient privileges, you may change the effective group ID of
     the shell process by assigning to this parameter.  Also (assuming
     sufficient privileges), you may start a single command with a
     different effective group ID by `(EGID=GID; command)'

EUID <S>
     The effective user ID of the shell process.  If you have sufficient
     privileges, you may change the effective user ID of the shell
     process by assigning to this parameter.  Also (assuming sufficient
     privileges), you may start a single command with a different
     effective user ID by `(EUID=UID; command)'

ERRNO <S>
     The value of errno (see man page errno(3)) as set by the most
     recently failed system call.  This value is system dependent and
     is intended for debugging purposes.  It is also useful with the
     zsh/system module which allows the number to be turned into a name
     or message.

GID <S>
     The real group ID of the shell process.  If you have sufficient
     privileges, you may change the group ID of the shell process by
     assigning to this parameter.  Also (assuming sufficient
     privileges), you may start a single command under a different
     group ID by `(GID=GID; command)'

HISTCMD
     The current history line number in an interactive shell, in other
     words the line number for the command that caused $HISTCMD to be
     read.

HOST
     The current hostname.

LINENO <S>
     The line number of the current line within the current script,
     sourced file, or shell function being executed, whichever was
     started most recently.  Note that in the case of shell functions
     the line number refers to the function as it appeared in the
     original definition, not necessarily as displayed by the functions
     builtin.

LOGNAME
     If the corresponding variable is not set in the environment of the
     shell, it is initialized to the login name corresponding to the
     current login session. This parameter is exported by default but
     this can be disabled using the typeset builtin.

MACHTYPE
     The machine type (microprocessor class or machine model), as
     determined at compile time.

OLDPWD
     The previous working directory.  This is set when the shell
     initializes and whenever the directory changes.

OPTARG <S>
     The value of the last option argument processed by the getopts
     command.

OPTIND <S>
     The index of the last option argument processed by the getopts
     command.

OSTYPE
     The operating system, as determined at compile time.

PPID <S>
     The process ID of the parent of the shell.  As for $$, the value
     indicates the parent of the original shell and does not change in
     subshells.

PWD
     The present working directory.  This is set when the shell
     initializes and whenever the directory changes.

RANDOM <S>
     A pseudo-random integer from 0 to 32767, newly generated each time
     this parameter is referenced.  The random number generator can be
     seeded by assigning a numeric value to RANDOM.

     The values of RANDOM form an intentionally-repeatable pseudo-random
     sequence; subshells that reference RANDOM will result in identical
     pseudo-random values unless the value of RANDOM is referenced or
     seeded in the parent shell in between subshell invocations.

SECONDS <S>
     The number of seconds since shell invocation.  If this parameter
     is assigned a value, then the value returned upon reference will
     be the value that was assigned plus the number of seconds since
     the assignment.

     Unlike other special parameters, the type of the SECONDS parameter
     can be changed using the typeset command.  Only integer and one of
     the floating point types are allowed.  For example, `typeset -F
     SECONDS' causes the value to be reported as a floating point
     number.  The value is available to microsecond accuracy, although
     the shell may show more or fewer digits depending on the use of
     typeset.  See the documentation for the builtin typeset in *note
     Shell Builtin Commands:: for more details.

SHLVL <S>
     Incremented by one each time a new shell is started.

signals
     An array containing the names of the signals.

TRY_BLOCK_ERROR <S>
     In an always block, indicates whether the preceding list of code
     caused an error.  The value is 1 to indicate an error, 0 otherwise.
     It may be reset, clearing the error condition.  See *note Complex
     Commands::

TTY
     The name of the tty associated with the shell, if any.

TTYIDLE <S>
     The idle time of the tty associated with the shell in seconds or
     -1 if there is no such tty.

UID <S>
     The real user ID of the shell process.  If you have sufficient
     privileges, you may change the user ID of the shell by assigning
     to this parameter.  Also (assuming sufficient privileges), you may
     start a single command under a different user ID by `(UID=UID;
     command)'

USERNAME <S>
     The username corresponding to the real user ID of the shell
     process.  If you have sufficient privileges, you may change the
     username (and also the user ID and group ID) of the shell by
     assigning to this parameter.  Also (assuming sufficient
     privileges), you may start a single command under a different
     username (and user ID and group ID) by `(USERNAME=USERNAME;
     command)'

VENDOR
     The vendor, as determined at compile time.

zsh_eval_context <S> <Z> (ZSH_EVAL_CONTEXT <S>)
     An array (colon-separated list) indicating the context of shell
     code that is being run.  Each time a piece of shell code that is
     stored within the shell is executed a string is temporarily
     appended to the array to indicate the type of operation that is
     being performed.  Read in order the array gives an indication of
     the stack of operations being performed with the most immediate
     context last.

     Note that the variable does not give information on syntactic
     context such as pipelines or subshells.  Use $ZSH_SUBSHELL to
     detect subshells.

     The context is one of the following:
    cmdarg
          Code specified by the -c option to the command line that
          invoked the shell.

    cmdsubst
          Command substitution using the `...` or $(...) construct.

    equalsubst
          File substitution using the =(...) construct.

    eval
          Code executed by the eval builtin.

    evalautofunc
          Code executed with the KSH_AUTOLOAD mechanism in order to
          define an autoloaded function.

    fc
          Code from the shell history executed by the -e option to the
          fc builtin.

    file
          Lines of code being read directly from a file, for example by
          the source builtin.

    filecode
          Lines of code being read from a .zwc file instead of directly
          from the source file.

    globqual
          Code executed by the e or + glob qualifier.

    globsort
          Code executed to order files by the o glob qualifier.

    insubst
          File substitution using the <(...) construct.

    loadautofunc
          Code read directly from a file to define an autoloaded
          function.

    outsubst
          File substitution using the >(...) construct.

    sched
          Code executed by the sched builtin.

    shfunc
          A shell function.

    stty
          Code passed to stty by the STTY environment variable.
          Normally this is passed directly to the system's stty command,
          so this value is unlikely to be seen in practice.

    style
          Code executed as part of a style retrieved by the zstyle
          builtin from the zsh/zutil module.

    toplevel
          The highest execution level of a script or interactive shell.

    trap
          Code executed as a trap defined by the trap builtin.  Traps
          defined as functions have the context shfunc.  As traps are
          asynchronous they may have a different hierarchy from other
          code.

    zpty
          Code executed by the zpty builtin from the zsh/zpty module.

    zregexparse-guard
          Code executed as a guard by the zregexparse command from the
          zsh/zutil module.

    zregexparse-action
          Code executed as an action by the zregexparse command from the
          zsh/zutil module.


ZSH_NAME
     Expands to the basename of the command used to invoke this instance
     of zsh.

ZSH_PATCHLEVEL
     The revision string for the version number of the ChangeLog file
     in the zsh distribution.  This is most useful in order to keep
     track of versions of the shell during development between releases;
     hence most users should not use it and should instead rely on
     $ZSH_VERSION.

zsh_scheduled_events
     See *note The zsh/sched Module::.

ZSH_SUBSHELL
     Readonly integer.  Initially zero, incremented each time the shell
     forks to create a subshell for executing code.  Hence `(print
     $ZSH_SUBSHELL)' and `print $(print $ZSH_SUBSHELL)' output 1, while
     `( (print $ZSH_SUBSHELL) )' outputs 2.

ZSH_VERSION
     The version number of the release of zsh.


File: zsh.info,  Node: Parameters Used By The Shell,  Prev: Parameters Set By The Shell,  Up: Parameters

15.6 Parameters Used By The Shell
=================================

The following parameters are used by the shell.

In cases where there are two parameters with an upper- and lowercase
form of the same name, such as path and PATH, the lowercase form is an
array and the uppercase form is a scalar with the elements of the array
joined together by colons.  These are similar to tied parameters
created via `typeset -T'.  The normal use for the colon-separated form
is for exporting to the environment, while the array form is easier to
manipulate within the shell.  Note that unsetting either of the pair
will unset the other; they retain their special properties when
recreated, and recreating one of the pair will recreate the other.


ARGV0
     If exported, its value is used as the argv[0] of external commands.
     Usually used in constructs like `ARGV0=emacs nethack'.

BAUD
     The rate in bits per second at which data reaches the terminal.
     The line editor will use this value in order to compensate for a
     slow terminal by delaying updates to the display until necessary.
     If the parameter is unset or the value is zero the compensation
     mechanism is turned off.  The parameter is not set by default.

     This parameter may be profitably set in some circumstances, e.g.
     for slow modems dialing into a communications server, or on a slow
     wide area network.  It should be set to the baud rate of the
     slowest part of the link for best performance.

cdpath <S> <Z> (CDPATH <S>)
     An array (colon-separated list) of directories specifying the
     search path for the cd command.

COLUMNS <S>
     The number of columns for this terminal session.  Used for
     printing select lists and for the line editor.

CORRECT_IGNORE
     If set, is treated as a pattern during spelling correction.  Any
     potential correction that matches the pattern is ignored.  For
     example, if the value is `_*' then completion functions (which, by
     convention, have names beginning with `_') will never be offered
     as spelling corrections.  The pattern does not apply to the
     correction of file names, as applied by the CORRECT_ALL option (so
     with the example just given files beginning with `_' in the current
     directory would still be completed).

DIRSTACKSIZE
     The maximum size of the directory stack.  If the stack gets larger
     than this, it will be truncated automatically.  This is useful
     with the AUTO_PUSHD option.

ENV
     If the ENV environment variable is set when zsh is invoked as sh
     or ksh, $ENV is sourced after the profile scripts.  The value of
     ENV is subjected to parameter expansion, command substitution, and
     arithmetic expansion before being interpreted as a pathname.  Note
     that ENV is _not_ used unless zsh is emulating `sh' or `ksh'.

FCEDIT
     The default editor for the fc builtin.  If FCEDIT is not set, the
     parameter EDITOR is used; if that is not set either, a builtin
     default, usually vi, is used.

fignore <S> <Z> (FIGNORE <S>)
     An array (colon separated list) containing the suffixes of files
     to be ignored during filename completion.  However, if completion
     only generates files with suffixes in this list, then these files
     are completed anyway.

fpath <S> <Z> (FPATH <S>)
     An array (colon separated list) of directories specifying the
     search path for function definitions.  This path is searched when
     a function with the -u attribute is referenced.  If an executable
     file is found, then it is read and executed in the current
     environment.

histchars <S>
     Three characters used by the shell's history and lexical analysis
     mechanism.  The first character signals the start of a history
     expansion (default `!').  The second character signals the start
     of a quick history substitution (default `^').  The third
     character is the comment character (default `#').

     The characters must be in the ASCII character set; any attempt to
     set histchars to characters with a locale-dependent meaning will be
     rejected with an error message.

HISTCHARS <S> <Z>
     Same as histchars.  (Deprecated.)

HISTFILE
     The file to save the history in when an interactive shell exits.
     If unset, the history is not saved.

HISTSIZE <S>
     The maximum number of events stored in the internal history list.
     If you use the HIST_EXPIRE_DUPS_FIRST option, setting this value
     larger than the SAVEHIST size will give you the difference as a
     cushion for saving duplicated history events.

HOME <S>
     The default argument for the cd command.  This is not set
     automatically by the shell in sh, ksh or csh emulation, but it is
     typically present in the environment anyway, and if it becomes set
     it has its usual special behaviour.

IFS <S>
     Internal field separators (by default space, tab, newline and
     NUL), that are used to separate words which result from command or
     parameter expansion and words read by the read builtin.  Any
     characters from the set space, tab and newline that appear in the
     IFS are called _IFS white space_.  One or more IFS white space
     characters or one non-IFS white space character together with any
     adjacent IFS white space character delimit a field.  If an IFS
     white space character appears twice consecutively in the IFS, this
     character is treated as if it were not an IFS white space
     character.

     If the parameter is unset, the default is used.  Note this has a
     different effect from setting the parameter to an empty string.

KEYBOARD_HACK
     This variable defines a character to be removed from the end of the
     command line before interpreting it (interactive shells only). It
     is intended to fix the problem with keys placed annoyingly close
     to return and replaces the SUNKEYBOARDHACK option which did this
     for backquotes only.  Should the chosen character be one of
     singlequote, doublequote or backquote, there must also be an odd
     number of them on the command line for the last one to be removed.

KEYTIMEOUT
     The time the shell waits, in hundredths of seconds, for another
     key to be pressed when reading bound multi-character sequences.

LANG <S>
     This variable determines the locale category for any category not
     specifically selected via a variable starting with `LC_'.

LC_ALL <S>
     This variable overrides the value of the `LANG' variable and the
     value of any of the other variables starting with `LC_'.

LC_COLLATE <S>
     This variable determines the locale category for character
     collation information within ranges in glob brackets and for
     sorting.

LC_CTYPE <S>
     This variable determines the locale category for character handling
     functions.  If the MULTIBYTE option is in effect this variable or
     LANG should contain a value that reflects the character set in
     use, even if it is a single-byte character set, unless only the
     7-bit subset (ASCII) is used.  For example, if the character set
     is ISO-8859-1, a suitable value might be en_US.iso88591 (certain
     Linux distributions) or en_US.ISO8859-1 (MacOS).

LC_MESSAGES <S>
     This variable determines the language in which messages should be
     written.  Note that zsh does not use message catalogs.

LC_NUMERIC <S>
     This variable affects the decimal point character and thousands
     separator character for the formatted input/output functions and
     string conversion functions.  Note that zsh ignores this setting
     when parsing floating point mathematical expressions.

LC_TIME <S>
     This variable determines the locale category for date and time
     formatting in prompt escape sequences.

LINES <S>
     The number of lines for this terminal session.  Used for printing
     select lists and for the line editor.

LISTMAX
     In the line editor, the number of matches to list without asking
     first. If the value is negative, the list will be shown if it
     spans at most as many lines as given by the absolute value.  If
     set to zero, the shell asks only if the top of the listing would
     scroll off the screen.

LOGCHECK
     The interval in seconds between checks for login/logout activity
     using the watch parameter.

MAIL
     If this parameter is set and mailpath is not set, the shell looks
     for mail in the specified file.

MAILCHECK
     The interval in seconds between checks for new mail.

mailpath <S> <Z> (MAILPATH <S>)
     An array (colon-separated list) of filenames to check for new
     mail.  Each filename can be followed by a `?' and a message that
     will be printed.  The message will undergo parameter expansion,
     command substitution and arithmetic expansion with the variable $_
     defined as the name of the file that has changed.  The default
     message is `You have new mail'.  If an element is a directory
     instead of a file the shell will recursively check every file in
     every subdirectory of the element.

manpath <S> <Z> (MANPATH <S> <Z>)
     An array (colon-separated list) whose value is not used by the
     shell.  The manpath array can be useful, however, since setting it
     also sets MANPATH, and vice versa.

module_path <S> <Z> (MODULE_PATH <S>)
     An array (colon-separated list) of directories that zmodload
     searches for dynamically loadable modules.  This is initialized to
     a standard pathname, usually `/usr/local/lib/zsh/$ZSH_VERSION'.
     (The `/usr/local/lib' part varies from installation to
     installation.)  For security reasons, any value set in the
     environment when the shell is started will be ignored.

     These parameters only exist if the installation supports dynamic
     module loading.

NULLCMD <S>
     The command name to assume if a redirection is specified with no
     command.  Defaults to cat.  For `sh'/`ksh' behavior, change this
     to :.  For `csh'-like behavior, unset this parameter; the shell
     will print an error message if null commands are entered.

path <S> <Z> (PATH <S>)
     An array (colon-separated list) of directories to search for
     commands.  When this parameter is set, each directory is scanned
     and all files found are put in a hash table.

POSTEDIT <S>
     This string is output whenever the line editor exits.  It usually
     contains termcap strings to reset the terminal.

PROMPT <S> <Z>
PROMPT2 <S> <Z>
PROMPT3 <S> <Z>
PROMPT4 <S> <Z>
     Same as PS1, PS2, PS3 and PS4, respectively.

prompt <S> <Z>
     Same as PS1.

PROMPT_EOL_MARK
     When the PROMPT_CR and PROMPT_SP options are set, the
     PROMPT_EOL_MARK parameter can be used to customize how the end of
     partial lines are shown.  This parameter undergoes prompt
     expansion, with the PROMPT_PERCENT option set.  If not set or
     empty, the default behavior is equivalent to the value
     `%B%S%#%s%b'.

PS1 <S>
     The primary prompt string, printed before a command is read.  It
     undergoes a special form of expansion before being displayed; see
     *note Prompt Expansion::.  The default is `%m%# '.

PS2 <S>
     The secondary prompt, printed when the shell needs more information
     to complete a command.  It is expanded in the same way as PS1.
     The default is `%_> ', which displays any shell constructs or
     quotation marks which are currently being processed.

PS3 <S>
     Selection prompt used within a select loop.  It is expanded in the
     same way as PS1.  The default is `?# '.

PS4 <S>
     The execution trace prompt.  Default is `+%N:%i> ', which displays
     the name of the current shell structure and the line number within
     it.  In sh or ksh emulation, the default is `+ '.

psvar <S> <Z> (PSVAR <S>)
     An array (colon-separated list) whose first nine values can be
     used in PROMPT strings.  Setting psvar also sets PSVAR, and vice
     versa.

READNULLCMD <S>
     The command name to assume if a single input redirection is
     specified with no command.  Defaults to more.

REPORTTIME
     If nonnegative, commands whose combined user and system execution
     times (measured in seconds) are greater than this value have timing
     statistics printed for them.

REPLY
     This parameter is reserved by convention to pass string values
     between shell scripts and shell builtins in situations where a
     function call or redirection are impossible or undesirable.  The
     read builtin and the select complex command may set REPLY, and
     filename generation both sets and examines its value when
     evaluating certain expressions.  Some modules also employ REPLY
     for similar purposes.

reply
     As REPLY, but for array values rather than strings.

RPROMPT <S>
RPS1 <S>
     This prompt is displayed on the right-hand side of the screen when
     the primary prompt is being displayed on the left.  This does not
     work if the SINGLELINEZLE option is set.  It is expanded in the
     same way as PS1.

RPROMPT2 <S>
RPS2 <S>
     This prompt is displayed on the right-hand side of the screen when
     the secondary prompt is being displayed on the left.  This does
     not work if the SINGLELINEZLE option is set.  It is expanded in
     the same way as PS2.

SAVEHIST
     The maximum number of history events to save in the history file.

SPROMPT <S>
     The prompt used for spelling correction.  The sequence `%R'
     expands to the string which presumably needs spelling correction,
     and `%r' expands to the proposed correction.  All other prompt
     escapes are also allowed.

STTY
     If this parameter is set in a command's environment, the shell
     runs the stty command with the value of this parameter as
     arguments in order to set up the terminal before executing the
     command. The modes apply only to the command, and are reset when
     it finishes or is suspended. If the command is suspended and
     continued later with the fg or wait builtins it will see the modes
     specified by STTY, as if it were not suspended.  This
     (intentionally) does not apply if the command is continued via
     `kill -CONT'.  STTY is ignored if the command is run in the
     background, or if it is in the environment of the shell but not
     explicitly assigned to in the input line. This avoids running stty
     at every external command by accidentally exporting it. Also note
     that STTY should not be used for window size specifications; these
     will not be local to the command.

TERM <S>
     The type of terminal in use.  This is used when looking up termcap
     sequences.  An assignment to TERM causes zsh to re-initialize the
     terminal, even if the value does not change (e.g., `TERM=$TERM').
     It is necessary to make such an assignment upon any change to the
     terminal definition database or terminal type in order for the new
     settings to take effect.

TIMEFMT
     The format of process time reports with the time keyword.  The
     default is `%E real  %U user  %S system  %P %J'.  Recognizes the
     following escape sequences, although not all may be available on
     all systems, and some that are available may not be useful:


    %%
          A `%'.

    %U
          CPU seconds spent in user mode.

    %S
          CPU seconds spent in kernel mode.

    %E
          Elapsed time in seconds.

    %P
          The CPU percentage, computed as (100*%U+%S)/%E.

    %W
          Number of times the process was swapped.

    %X
          The average amount in (shared) text space used in Kbytes.

    %D
          The average amount in (unshared) data/stack space used in
          Kbytes.

    %K
          The total space used (%X+%D) in Kbytes.

    %M
          The  maximum memory the process had in use at any time in
          Kbytes.

    %F
          The number of major page faults (page needed to be brought
          from disk).

    %R
          The number of minor page faults.

    %I
          The number of input operations.

    %O
          The number of output operations.

    %r
          The number of socket messages received.

    %s
          The number of socket messages sent.

    %k
          The number of signals received.

    %w
          Number of voluntary context switches (waits).

    %c
          Number of involuntary context switches.

    %J
          The name of this job.

     A star may be inserted between the percent sign and flags printing
     time.  This cause the time to be printed in `HH:MM:SS.TTT' format
     (hours and minutes are only printed if they are not zero).

TMOUT
     If this parameter is nonzero, the shell will receive an ALRM
     signal if a command is not entered within the specified number of
     seconds after issuing a prompt. If there is a trap on SIGALRM, it
     will be executed and a new alarm is scheduled using the value of
     the TMOUT parameter after executing the trap.  If no trap is set,
     and the idle time of the terminal is not less than the value of the
     TMOUT parameter, zsh terminates.  Otherwise a new alarm is
     scheduled to TMOUT seconds after the last keypress.

TMPPREFIX
     A pathname prefix which the shell will use for all temporary files.
     Note that this should include an initial part for the file name as
     well as any directory names.  The default is `/tmp/zsh'.

watch <S> <Z> (WATCH <S>)
     An array (colon-separated list) of login/logout events to report.
     If it contains the single word `all', then all login/logout events
     are reported.  If it contains the single word `notme', then all
     events are reported as with `all' except $USERNAME.  An entry in
     this list may consist of a username, an `@' followed by a remote
     hostname, and a `%' followed by a line (tty).  Any or all of these
     components may be present in an entry; if a login/logout event
     matches all of them, it is reported.

WATCHFMT
     The format of login/logout reports if the watch parameter is set.
     Default is `%n has %a %l from %m'.  Recognizes the following
     escape sequences:


    %n
          The name of the user that logged in/out.

    %a
          The observed action, i.e. "logged on" or "logged off".

    %l
          The line (tty) the user is logged in on.

    %M
          The full hostname of the remote host.

    %m
          The hostname up to the first `.'.  If only the IP address is
          available or the utmp field contains the name of an X-windows
          display, the whole name is printed.

          _NOTE:_ The `%m' and `%M' escapes will work only if there is
          a host name field in the utmp on your machine.  Otherwise
          they are treated as ordinary strings.

    %S (%s)
          Start (stop) standout mode.

    %U (%u)
          Start (stop) underline mode.

    %B (%b)
          Start (stop) boldface mode.

    %t
    %@
          The time, in 12-hour, am/pm format.

    %T
          The time, in 24-hour format.

    %w
          The date in `DAY-DD' format.

    %W
          The date in `MM/DD/YY' format.

    %D
          The date in `YY-MM-DD' format.

    %(X:TRUE-TEXT:FALSE-TEXT)
          Specifies a ternary expression.  The character following the
          X is arbitrary; the same character is used to separate the
          text for the "true" result from that for the "false" result.
          Both the separator and the right parenthesis may be escaped
          with a backslash.  Ternary expressions may be nested.

          The test character X may be any one of `l', `n', `m' or `M',
          which indicate a `true' result if the corresponding escape
          sequence would return a non-empty value; or it may be `a',
          which indicates a `true' result if the watched user has
          logged in, or `false' if he has logged out.  Other characters
          evaluate to neither true nor false; the entire expression is
          omitted in this case.

          If the result is `true', then the TRUE-TEXT is formatted
          according to the rules above and printed, and the FALSE-TEXT
          is skipped.  If `false', the TRUE-TEXT is skipped and the
          FALSE-TEXT is formatted and printed.  Either or both of the
          branches may be empty, but both separators must be present in
          any case.


WORDCHARS <S>
     A list of non-alphanumeric characters considered part of a word by
     the line editor.

ZBEEP
     If set, this gives a string of characters, which can use all the
     same codes as the bindkey command as described in *note The
     zsh/zle Module::, that will be output to the terminal instead of
     beeping.  This may have a visible instead of an audible effect;
     for example, the string `\e[?5h\e[?5l' on a vt100 or xterm will
     have the effect of flashing reverse video on and off (if you
     usually use reverse video, you should use the string
     `\e[?5l\e[?5h' instead).  This takes precedence over the NOBEEP
     option.

ZDOTDIR
     The directory to search for shell startup files (.zshrc, etc), if
     not $HOME.

ZLE_LINE_ABORTED
     This parameter is set by the line editor when an error occurs.  It
     contains the line that was being edited at the point of the error.
     `print -zr - $ZLE_LINE_ABORTED' can be used to recover the line.
     Only the most recent line of this kind is remembered.

ZLE_REMOVE_SUFFIX_CHARS
ZLE_SPACE_SUFFIX_CHARS
     These parameters are used by the line editor.  In certain
     circumstances suffixes (typically space or slash) added by the
     completion system will be removed automatically, either because
     the next editing command was not an insertable character, or
     because the character was marked as requiring the suffix to be
     removed.

     These variables can contain the sets of characters that will cause
     the suffix to be removed.  If ZLE_REMOVE_SUFFIX_CHARS is set, those
     characters will cause the suffix to be removed; if
     ZLE_SPACE_SUFFIX_CHARS is set, those characters will cause the
     suffix to be removed and replaced by a space.

     If ZLE_REMOVE_SUFFIX_CHARS is not set, the default behaviour is
     equivalent to:


          ZLE_REMOVE_SUFFIX_CHARS=$' \t\n;&|'

     If ZLE_REMOVE_SUFFIX_CHARS is set but is empty, no characters have
     this behaviour.  ZLE_SPACE_SUFFIX_CHARS takes precedence, so that
     the following:


          ZLE_SPACE_SUFFIX_CHARS=$'&|'

     causes the characters `&' and `|' to remove the suffix but to
     replace it with a space.

     To illustrate the difference, suppose that the option
     AUTO_REMOVE_SLASH is in effect and the directory DIR has just been
     completed, with an appended /, following which the user types `&'.
     The default result is `DIR&'.  With ZLE_REMOVE_SUFFIX_CHARS set
     but without including `&' the result is `DIR/&'.  With
     ZLE_SPACE_SUFFIX_CHARS set to include `&' the result is `DIR &'.

     Note that certain completions may provide their own suffix removal
     or replacement behaviour which overrides the values described here.
     See the completion system documentation in *note Completion
     System::.


File: zsh.info,  Node: Options,  Next: Shell Builtin Commands,  Prev: Parameters,  Up: Top

16 Options
**********



* Menu:

* Specifying Options::
* Description of Options::
* Option Aliases::
* Single Letter Options::

File: zsh.info,  Node: Specifying Options,  Next: Description of Options,  Up: Options

16.1 Specifying Options
=======================

Options are primarily referred to by name.  These names are case
insensitive and underscores are ignored.  For example, `allexport' is
equivalent to `A__lleXP_ort'.

The sense of an option name may be inverted by preceding it with `no',
so `setopt No_Beep' is equivalent to `unsetopt beep'.  This inversion
can only be done once, so `nonobeep' is _not_ a synonym for `beep'.
Similarly, `tify' is not a synonym for `nonotify' (the inversion of
`notify').

Some options also have one or more single letter names.  There are two
sets of single letter options: one used by default, and another used to
emulate `sh'/`ksh' (used when the SH_OPTION_LETTERS option is set).
The single letter options can be used on the shell command line, or
with the set, setopt and unsetopt builtins, as normal Unix options
preceded by `-'.

The sense of the single letter options may be inverted by using `+'
instead of `-'.  Some of the single letter option names refer to an
option being off, in which case the inversion of that name refers to
the option being on.  For example, `+n' is the short name of `exec', and
`-n' is the short name of its inversion, `noexec'.

In strings of single letter options supplied to the shell at startup,
trailing whitespace will be ignored; for example the string `-f    '
will be treated just as `-f', but the string `-f i' is an error.  This
is because many systems which implement the `#!' mechanism for calling
scripts do not strip trailing whitespace.



File: zsh.info,  Node: Description of Options,  Next: Option Aliases,  Prev: Specifying Options,  Up: Options

16.2 Description of Options
===========================

In the following list, options set by default in all emulations are
marked <D>; those set by default only in csh, ksh, sh, or zsh
emulations are marked <C>, <K>, <S>, <Z> as appropriate.  When listing
options (by `setopt', `unsetopt', `set -o' or `set +o'), those turned
on by default appear in the list prefixed with `no'.  Hence (unless
KSH_OPTION_PRINT is set), `setopt' shows all options whose settings are
changed from the default.



16.2.1 Changing Directories
---------------------------


AUTO_CD (-J)
     If a command is issued that can't be executed as a normal command,
     and the command is the name of a directory, perform the cd command
     to that directory.

AUTO_PUSHD (-N)
     Make cd push the old directory onto the directory stack.

CDABLE_VARS (-T)
     If the argument to a cd command (or an implied cd with the AUTO_CD
     option set) is not a directory, and does not begin with a slash,
     try to expand the expression as if it were preceded by a `~' (see
     *note Filename Expansion::).

CHASE_DOTS
     When changing to a directory containing a path segment `..' which
     would otherwise be treated as canceling the previous segment in
     the path (in other words, `foo/..' would be removed from the path,
     or if `..' is the first part of the path, the last part of the
     current working directory would be removed), instead resolve the
     path to the physical directory.  This option is overridden by
     CHASE_LINKS.

     For example, suppose /foo/bar is a link to the directory /alt/rod.
     Without this option set, `cd /foo/bar/..' changes to /foo; with it
     set, it changes to /alt.  The same applies if the current directory
     is /foo/bar and `cd ..' is used.  Note that all other symbolic
     links in the path will also be resolved.

CHASE_LINKS (-w)
     Resolve symbolic links to their true values when changing
     directory.  This also has the effect of CHASE_DOTS, i.e. a `..'
     path segment will be treated as referring to the physical parent,
     even if the preceding path segment is a symbolic link.

POSIX_CD
     Modifies the behaviour of cd, chdir and pushd commands to make
     them more compatible with the POSIX standard. The behaviour with
     the option unset is described in the documentation for the cd
     builtin in *note Shell Builtin Commands::.  If the option is set,
     the shell does not test for directories beneath the local
     directory (`.') until after all directories in cdpath have been
     tested.

     Also, if the option is set, the conditions under which the shell
     prints the new directory after changing to it are modified.  It is
     no longer restricted to interactive shells (although printing of
     the directory stack with pushd is still limited to interactive
     shells); and any use of a component of CDPATH, including a `.' but
     excluding an empty component that is otherwise treated as `.',
     causes the directory to be printed.

PUSHD_IGNORE_DUPS
     Don't push multiple copies of the same directory onto the
     directory stack.

PUSHD_MINUS
     Exchanges the meanings of `+' and `-' when used with a number to
     specify a directory in the stack.

PUSHD_SILENT (-E)
     Do not print the directory stack after pushd or popd.

PUSHD_TO_HOME (-D)
     Have pushd with no arguments act like `pushd $HOME'.



16.2.2 Completion
-----------------


ALWAYS_LAST_PROMPT <D>
     If unset, key functions that list completions try to return to the
     last prompt if given a numeric argument. If set these functions
     try to return to the last prompt if given _no_ numeric argument.

ALWAYS_TO_END
     If a completion is performed with the cursor within a word, and a
     full completion is inserted, the cursor is moved to the end of the
     word.  That is, the cursor is moved to the end of the word if
     either a single match is inserted or menu completion is performed.

AUTO_LIST (-9) <D>
     Automatically list choices on an ambiguous completion.

AUTO_MENU <D>
     Automatically use menu completion after the second consecutive
     request for completion, for example by pressing the tab key
     repeatedly. This option is overridden by MENU_COMPLETE.

AUTO_NAME_DIRS
     Any parameter that is set to the absolute name of a directory
     immediately becomes a name for that directory, that will be used
     by the `%~' and related prompt sequences, and will be available
     when completion is performed on a word starting with `~'.
     (Otherwise, the parameter must be used in the form `~PARAM' first.)

AUTO_PARAM_KEYS <D>
     If a parameter name was completed and a following character
     (normally a space) automatically inserted, and the next character
     typed is one of those that have to come directly after the name
     (like `}', `:', etc.), the automatically added character is
     deleted, so that the character typed comes immediately after the
     parameter name.  Completion in a brace expansion is affected
     similarly: the added character is a `,', which will be removed if
     `}' is typed next.

AUTO_PARAM_SLASH <D>
     If a parameter is completed whose content is the name of a
     directory, then add a trailing slash instead of a space.

AUTO_REMOVE_SLASH <D>
     When the last character resulting from a completion is a slash and
     the next character typed is a word delimiter, a slash, or a
     character that ends a command (such as a semicolon or an
     ampersand), remove the slash.

BASH_AUTO_LIST
     On an ambiguous completion, automatically list choices when the
     completion function is called twice in succession.  This takes
     precedence over AUTO_LIST.  The setting of LIST_AMBIGUOUS is
     respected.  If AUTO_MENU is set, the menu behaviour will then start
     with the third press.  Note that this will not work with
     MENU_COMPLETE, since repeated completion calls immediately cycle
     through the list in that case.

COMPLETE_ALIASES
     Prevents aliases on the command line from being internally
     substituted before completion is attempted.  The effect is to make
     the alias a distinct command for completion purposes.

COMPLETE_IN_WORD
     If unset, the cursor is set to the end of the word if completion is
     started. Otherwise it stays there and completion is done from both
     ends.

GLOB_COMPLETE
     When the current word has a glob pattern, do not insert all the
     words resulting from the expansion but generate matches as for
     completion and cycle through them like MENU_COMPLETE. The matches
     are generated as if a `*' was added to the end of the word, or
     inserted at the cursor when COMPLETE_IN_WORD is set.  This
     actually uses pattern matching, not globbing, so it works not only
     for files but for any completion, such as options, user names, etc.

     Note that when the pattern matcher is used, matching control (for
     example, case-insensitive or anchored matching) cannot be used.
     This limitation only applies when the current word contains a
     pattern; simply turning on the GLOB_COMPLETE option does not have
     this effect.

HASH_LIST_ALL <D>
     Whenever a command completion is attempted, make sure the entire
     command path is hashed first.  This makes the first completion
     slower.

LIST_AMBIGUOUS <D>
     This option works when AUTO_LIST or BASH_AUTO_LIST is also set.
     If there is an unambiguous prefix to insert on the command line,
     that is done without a completion list being displayed; in other
     words, auto-listing behaviour only takes place when nothing would
     be inserted.  In the case of BASH_AUTO_LIST, this means that the
     list will be delayed to the third call of the function.

LIST_BEEP <D>
     Beep on an ambiguous completion.  More accurately, this forces the
     completion widgets to return status 1 on an ambiguous completion,
     which causes the shell to beep if the option BEEP is also set;
     this may be modified if completion is called from a user-defined
     widget.

LIST_PACKED
     Try to make the completion list smaller (occupying less lines) by
     printing the matches in columns with different widths.

LIST_ROWS_FIRST
     Lay out the matches in completion lists sorted horizontally, that
     is, the second match is to the right of the first one, not under
     it as usual.

LIST_TYPES (-X) <D>
     When listing files that are possible completions, show the type of
     each file with a trailing identifying mark.

MENU_COMPLETE (-Y)
     On an ambiguous completion, instead of listing possibilities or
     beeping, insert the first match immediately.  Then when completion
     is requested again, remove the first match and insert the second
     match, etc.  When there are no more matches, go back to the first
     one again.  reverse-menu-complete may be used to loop through the
     list in the other direction. This option overrides AUTO_MENU.

REC_EXACT (-S)
     In completion, recognize exact matches even if they are ambiguous.



16.2.3 Expansion and Globbing
-----------------------------


BAD_PATTERN (+2) <C> <Z>
     If a pattern for filename generation is badly formed, print an
     error message.  (If this option is unset, the pattern will be left
     unchanged.)

BARE_GLOB_QUAL <Z>
     In a glob pattern, treat a trailing set of parentheses as a
     qualifier list, if it contains no `|', `(' or (if special) `~'
     characters.  See *note Filename Generation::.

BRACE_CCL
     Expand expressions in braces which would not otherwise undergo
     brace expansion to a lexically ordered list of all the characters.
     See *note Brace Expansion::.

CASE_GLOB <D>
     Make globbing (filename generation) sensitive to case.  Note that
     other uses of patterns are always sensitive to case.  If the
     option is unset, the presence of any character which is special to
     filename generation will cause case-insensitive matching.  For
     example, cvs(/) can match the directory CVS owing to the presence
     of the globbing flag (unless the option BARE_GLOB_QUAL is unset).

CASE_MATCH <D>
     Make regular expressions using the zsh/regex module (including
     matches with =~) sensitive to case.

CSH_NULL_GLOB <C>
     If a pattern for filename generation has no matches, delete the
     pattern from the argument list; do not report an error unless all
     the patterns in a command have no matches.  Overrides NOMATCH.

EQUALS <Z>
     Perform = filename expansion.  (See *note Filename Expansion::.)

EXTENDED_GLOB
     Treat the `#', `~' and `^' characters as part of patterns for
     filename generation, etc.  (An initial unquoted `~' always
     produces named directory expansion.)

GLOB (+F, ksh: +f) <D>
     Perform filename generation (globbing).  (See *note Filename
     Generation::.)

GLOB_ASSIGN <C>
     If this option is set, filename generation (globbing) is performed
     on the right hand side of scalar parameter assignments of the form
     `NAME=PATTERN (e.g. `foo=*').  If the result has more than one
     word the parameter will become an array with those words as
     arguments. This option is provided for backwards compatibility
     only: globbing is always performed on the right hand side of array
     assignments of the form `NAME=(VALUE)' (e.g. `foo=(*)') and this
     form is recommended for clarity; with this option set, it is not
     possible to predict whether the result will be an array or a
     scalar.

GLOB_DOTS (-4)
     Do not require a leading `.' in a filename to be matched
     explicitly.

GLOB_SUBST <C> <K> <S>
     Treat any characters resulting from parameter expansion as being
     eligible for file expansion and filename generation, and any
     characters resulting from command substitution as being eligible
     for filename generation.  Braces (and commas in between) do not
     become eligible for expansion.

HIST_SUBST_PATTERN
     Substitutions using the :s and :& history modifiers are performed
     with pattern matching instead of string matching.  This occurs
     wherever history modifiers are valid, including glob qualifiers
     and parameters.  See *note Modifiers::.

IGNORE_BRACES (-I) <S>
     Do not perform brace expansion.

KSH_GLOB <K>
     In pattern matching, the interpretation of parentheses is affected
     by a preceding `@', `*', `+', `?' or `!'.  See *note Filename
     Generation::.

MAGIC_EQUAL_SUBST
     All unquoted arguments of the form `ANYTHING=EXPRESSION' appearing
     after the command name have filename expansion (that is, where
     EXPRESSION has a leading `~' or `=') performed on EXPRESSION as if
     it were a parameter assignment.  The argument is not otherwise
     treated specially; it is passed to the command as a single
     argument, and not used as an actual parameter assignment.  For
     example, in echo foo=~/bar:~/rod, both occurrences of ~ would be
     replaced.  Note that this happens anyway with typeset and similar
     statements.

     This option respects the setting of the KSH_TYPESET option.  In
     other words, if both options are in effect, arguments looking like
     assignments will not undergo word splitting.

MARK_DIRS (-8, ksh: -X)
     Append a trailing `/' to all directory names resulting from
     filename generation (globbing).

MULTIBYTE <C> <K> <Z>
     Respect multibyte characters when found in strings.  When this
     option is set, strings are examined using the system library to
     determine how many bytes form a character, depending on the
     current locale.  This affects the way characters are counted in
     pattern matching, parameter values and various delimiters.

     The option is on by default if the shell was compiled with
     MULTIBYTE_SUPPORT except in sh emulation; otherwise it is off by
     default and has no effect if turned on.  The mode is off in sh
     emulation for compatibility but for interactive use may need to be
     turned on if the terminal interprets multibyte characters.

     If the option is off a single byte is always treated as a single
     character.  This setting is designed purely for examining strings
     known to contain raw bytes or other values that may not be
     characters in the current locale.  It is not necessary to unset
     the option merely because the character set for the current locale
     does not contain multibyte characters.

     The option does not affect the shell's editor,  which always uses
     the locale to determine multibyte characters.  This is because the
     character set displayed by the terminal emulator is independent of
     shell settings.

NOMATCH (+3) <C> <Z>
     If a pattern for filename generation has no matches, print an
     error, instead of leaving it unchanged in the argument list.  This
     also applies to file expansion of an initial `~' or `='.

NULL_GLOB (-G)
     If a pattern for filename generation has no matches, delete the
     pattern from the argument list instead of reporting an error.
     Overrides NOMATCH.

NUMERIC_GLOB_SORT
     If numeric filenames are matched by a filename generation pattern,
     sort the filenames numerically rather than lexicographically.

RC_EXPAND_PARAM (-P)
     Array expansions of the form `FOO${XX}BAR', where the parameter XX
     is set to (A B C), are substituted with `FOOABAR FOOBBAR FOOCBAR'
     instead of the default `FOOA B CBAR'.  Note that an empty array
     will therefore cause all arguments to be removed.

REMATCH_PCRE <Z>
     If set, regular expression matching with the =~ operator will use
     Perl-Compatible Regular Expressions from the PCRE library, if
     available.  If not set, regular expressions will use the extended
     regexp syntax provided by the system libraries.

SH_GLOB <K> <S>
     Disables the special meaning of `(', `|', `)' and '<' for globbing
     the result of parameter and command substitutions, and in some
     other places where the shell accepts patterns.  This option is set
     by default if zsh is invoked as sh or ksh.

UNSET (+u, ksh: +u) <K> <S> <Z>
     Treat unset parameters as if they were empty when substituting.
     Otherwise they are treated as an error.

WARN_CREATE_GLOBAL
     Print a warning message when a global parameter is created in a
     function by an assignment.  This often indicates that a parameter
     has not been declared local when it should have been.  Parameters
     explicitly declared global from within a function using typeset -g
     do not cause a warning.  Note that there is no warning when a
     local parameter is assigned to in a nested function, which may
     also indicate an error.



16.2.4 History
--------------


APPEND_HISTORY <D>
     If this is set, zsh sessions will append their history list to the
     history file, rather than replace it. Thus, multiple parallel zsh
     sessions will all have the new entries from their history lists
     added to the history file, in the order that they exit.  The file
     will still be periodically re-written to trim it when the number
     of lines grows 20% beyond the value specified by $SAVEHIST (see
     also the HIST_SAVE_BY_COPY option).

BANG_HIST (+K) <C> <Z>
     Perform textual history expansion, `csh'-style, treating the
     character `!' specially.

EXTENDED_HISTORY <C>
     Save each command's beginning timestamp (in seconds since the
     epoch) and the duration (in seconds) to the history file.  The
     format of this prefixed data is:

     `: <BEGINNING TIME>:<ELAPSED SECONDS>;<COMMAND>'.

HIST_ALLOW_CLOBBER
     Add `|' to output redirections in the history.  This allows history
     references to clobber files even when CLOBBER is unset.

HIST_BEEP <D>
     Beep when an attempt is made to access a history entry which isn't
     there.

HIST_EXPIRE_DUPS_FIRST
     If the internal history needs to be trimmed to add the current
     command line, setting this option will cause the oldest history
     event that has a duplicate to be lost before losing a unique event
     from the list.  You should be sure to set the value of HISTSIZE to
     a larger number than SAVEHIST in order to give you some room for
     the duplicated events, otherwise this option will behave just like
     HIST_IGNORE_ALL_DUPS once the history fills up with unique events.

HIST_FCNTL_LOCK
     When writing out the history file, by default zsh uses ad-hoc file
     locking to avoid known problems with locking on some operating
     systems.  With this option locking is done by means of the
     system's fcntl call, where this method is available.  On recent
     operating systems this may provide better performance, in
     particular avoiding history corruption when files are stored on
     NFS.

HIST_FIND_NO_DUPS
     When searching for history entries in the line editor, do not
     display duplicates of a line previously found, even if the
     duplicates are not contiguous.

HIST_IGNORE_ALL_DUPS
     If a new command line being added to the history list duplicates an
     older one, the older command is removed from the list (even if it
     is not the previous event).

HIST_IGNORE_DUPS (-h)
     Do not enter command lines into the history list if they are
     duplicates of the previous event.

HIST_IGNORE_SPACE (-g)
     Remove command lines from the history list when the first
     character on the line is a space, or when one of the expanded
     aliases contains a leading space.  Only normal aliases (not global
     or suffix aliases) have this behaviour.  Note that the command
     lingers in the internal history until the next command is entered
     before it vanishes, allowing you to briefly reuse or edit the
     line.  If you want to make it vanish right away without entering
     another command, type a space and press return.

HIST_LEX_WORDS
     By default, shell history that is read in from files is split into
     words on all white space.  This means that arguments with quoted
     whitespace are not correctly handled, with the consequence that
     references to words in history lines that have been read from a
     file may be inaccurate.  When this option is set, words read in
     from a history file are divided up in a similar fashion to normal
     shell command line handling.  Although this produces more
     accurately delimited words, if the size of the history file is
     large this can be slow.  Trial and error is necessary to decide.

HIST_NO_FUNCTIONS
     Remove function definitions from the history list.  Note that the
     function lingers in the internal history until the next command is
     entered before it vanishes, allowing you to briefly reuse or edit
     the definition.

HIST_NO_STORE
     Remove the history (fc -l) command from the history list when
     invoked.  Note that the command lingers in the internal history
     until the next command is entered before it vanishes, allowing you
     to briefly reuse or edit the line.

HIST_REDUCE_BLANKS
     Remove superfluous blanks from each command line being added to
     the history list.

HIST_SAVE_BY_COPY <D>
     When the history file is re-written, we normally write out a copy
     of the file named $HISTFILE.new and then rename it over the old
     one.  However, if this option is unset, we instead truncate the old
     history file and write out the new version in-place.  If one of the
     history-appending options is enabled, this option only has an
     effect when the enlarged history file needs to be re-written to
     trim it down to size.  Disable this only if you have special
     needs, as doing so makes it possible to lose history entries if
     zsh gets interrupted during the save.

     When writing out a copy of the history file, zsh preserves the old
     file's permissions and group information, but will refuse to write
     out a new file if it would change the history file's owner.

HIST_SAVE_NO_DUPS
     When writing out the history file, older commands that duplicate
     newer ones are omitted.

HIST_VERIFY
     Whenever the user enters a line with history expansion, don't
     execute the line directly; instead, perform history expansion and
     reload the line into the editing buffer.

INC_APPEND_HISTORY
     This options works like APPEND_HISTORY except that new history
     lines are added to the $HISTFILE incrementally (as soon as they are
     entered), rather than waiting until the shell exits.  The file
     will still be periodically re-written to trim it when the number
     of lines grows 20% beyond the value specified by $SAVEHIST (see
     also the HIST_SAVE_BY_COPY option).

SHARE_HISTORY <K>
     This option both imports new commands from the history file, and
     also causes your typed commands to be appended to the history file
     (the latter is like specifying INC_APPEND_HISTORY).  The history
     lines are also output with timestamps ala EXTENDED_HISTORY (which
     makes it easier to find the spot where we left off reading the
     file after it gets re-written).

     By default, history movement commands visit the imported lines as
     well as the local lines, but you can toggle this on and off with
     the set-local-history zle binding.  It is also possible to create
     a zle widget that will make some commands ignore imported
     commands, and some include them.

     If you find that you want more control over when commands get
     imported, you may wish to turn SHARE_HISTORY off,
     INC_APPEND_HISTORY on, and then manually import commands whenever
     you need them using `fc -RI'.



16.2.5 Initialisation
---------------------


ALL_EXPORT (-a, ksh: -a)
     All parameters subsequently defined are automatically exported.

GLOBAL_EXPORT (<Z>)
     If this option is set, passing the -x flag to the builtins declare,
     float, integer, readonly and typeset (but not local) will also set
     the -g flag;  hence parameters exported to the environment will
     not be made local to the enclosing function, unless they were
     already or the flag +g is given explicitly.  If the option is
     unset, exported parameters will be made local in just the same way
     as any other parameter.

     This option is set by default for backward compatibility; it is not
     recommended that its behaviour be relied upon.  Note that the
     builtin export always sets both the -x and -g flags, and hence its
     effect extends beyond the scope of the enclosing function; this is
     the most portable way to achieve this behaviour.

GLOBAL_RCS (-d) <D>
     If this option is unset, the startup files /etc/zprofile,
     /etc/zshrc, /etc/zlogin and /etc/zlogout will not be run.  It can
     be disabled and re-enabled at any time, including inside local
     startup files (.zshrc, etc.).

RCS (+f) <D>
     After /etc/zshenv is sourced on startup, source the .zshenv,
     /etc/zprofile, .zprofile, /etc/zshrc, .zshrc, /etc/zlogin,
     .zlogin, and .zlogout files, as described in *note Files::.  If
     this option is unset, the /etc/zshenv file is still sourced, but
     any of the others will not be; it can be set at any time to
     prevent the remaining startup files after the currently executing
     one from being sourced.



16.2.6 Input/Output
-------------------


ALIASES <D>
     Expand aliases.

CLOBBER (+C, ksh: +C) <D>
     Allows `>' redirection to truncate existing files, and `>>' to
     create files.  Otherwise `>!' or `>|' must be used to truncate a
     file, and `>>!' or `>>|' to create a file.

CORRECT (-0)
     Try to correct the spelling of commands.  Note that, when the
     HASH_LIST_ALL option is not set or when some directories in the
     path are not readable, this may falsely report spelling errors the
     first time some commands are used.

     The shell variable CORRECT_IGNORE may be set to a pattern to match
     words that will never be offered as corrections.

CORRECT_ALL (-O)
     Try to correct the spelling of all arguments in a line.

DVORAK
     Use the Dvorak keyboard instead of the standard qwerty keyboard as
     a basis for examining spelling mistakes for the CORRECT and
     CORRECT_ALL options and the spell-word editor command.

FLOW_CONTROL <D>
     If this option is unset, output flow control via start/stop
     characters (usually assigned to ^S/^Q) is disabled in the shell's
     editor.

IGNORE_EOF (-7)
     Do not exit on end-of-file.  Require the use of exit or logout
     instead.  However, ten consecutive EOFs will cause the shell to
     exit anyway, to avoid the shell hanging if its tty goes away.

     Also, if this option is set and the Zsh Line Editor is used,
     widgets implemented by shell functions can be bound to EOF
     (normally Control-D) without printing the normal warning message.
     This works only for normal widgets, not for completion widgets.

INTERACTIVE_COMMENTS (-k) <K> <S>
     Allow comments even in interactive shells.

HASH_CMDS <D>
     Note the location of each command the first time it is executed.
     Subsequent invocations of the same command will use the saved
     location, avoiding a path search.  If this option is unset, no
     path hashing is done at all.  However, when CORRECT is set,
     commands whose names do not appear in the functions or aliases
     hash tables are hashed in order to avoid reporting them as
     spelling errors.

HASH_DIRS <D>
     Whenever a command name is hashed, hash the directory containing
     it, as well as all directories that occur earlier in the path.
     Has no effect if neither HASH_CMDS nor CORRECT is set.

MAIL_WARNING (-U)
     Print a warning message if a mail file has been accessed since the
     shell last checked.

PATH_DIRS (-Q)
     Perform a path search even on command names with slashes in them.
     Thus if `/usr/local/bin' is in the user's path, and he or she types
     `X11/xinit', the command `/usr/local/bin/X11/xinit' will be
     executed (assuming it exists).  Commands explicitly beginning with
     `/', `./' or `../' are not subject to the path search.  This also
     applies to the `.' builtin.

     Note that subdirectories of the current directory are always
     searched for executables specified in this form.  This takes place
     before any search indicated by this option, and regardless of
     whether `.' or the current directory appear in the command search
     path.

PATH_SCRIPT <K> <S>
     If this option is not set, a script passed as the first non-option
     argument to the shell must contain the name of the file to open.
     If this option is set, and the script does not specify a directory
     path, the script is looked for first in the current directory,
     then in the command path.  See *note Invocation::.

PRINT_EIGHT_BIT
     Print eight bit characters literally in completion lists, etc.
     This option is not necessary if your system correctly returns the
     printability of eight bit characters (see man page ctype(3)).

PRINT_EXIT_VALUE (-1)
     Print the exit value of programs with non-zero exit status.

RC_QUOTES
     Allow the character sequence `''' to signify a single quote within
     singly quoted strings.  Note this does not apply in quoted strings
     using the format $'...', where a backslashed single quote can be
     used.

RM_STAR_SILENT (-H) <K> <S>
     Do not query the user before executing `rm *' or `rm path/*'.

RM_STAR_WAIT
     If querying the user before executing `rm *' or `rm path/*', first
     wait ten seconds and ignore anything typed in that time.  This
     avoids the problem of reflexively answering `yes' to the query
     when one didn't really mean it.  The wait and query can always be
     avoided by expanding the `*' in ZLE (with tab).

SHORT_LOOPS <C> <Z>
     Allow the short forms of for, repeat, select, if, and function
     constructs.

SUN_KEYBOARD_HACK (-L)
     If a line ends with a backquote, and there are an odd number of
     backquotes on the line, ignore the trailing backquote.  This is
     useful on some keyboards where the return key is too small, and
     the backquote key lies annoyingly close to it.  As an alternative
     the variable KEYBOARD_HACK lets you choose the character to be
     removed.



16.2.7 Job Control
------------------


AUTO_CONTINUE
     With this option set, stopped jobs that are removed from the job
     table with the disown builtin command are automatically sent a CONT
     signal to make them running.

AUTO_RESUME (-W)
     Treat single word simple commands without redirection as
     candidates for resumption of an existing job.

BG_NICE (-6) <C> <Z>
     Run all background jobs at a lower priority.  This option is set
     by default.

CHECK_JOBS <Z>
     Report the status of background and suspended jobs before exiting
     a shell with job control; a second attempt to exit the shell will
     succeed.  NO_CHECK_JOBS is best used only in combination with
     NO_HUP, else such jobs will be killed automatically.

     The check is omitted if the commands run from the previous command
     line included a `jobs' command, since it is assumed the user is
     aware that there are background or suspended jobs.  A `jobs'
     command run from one of the hook functions defined in the section
     Special Functions in *note Functions:: is not counted for this
     purpose.

HUP <Z>
     Send the HUP signal to running jobs when the shell exits.

LONG_LIST_JOBS (-R)
     List jobs in the long format by default.

MONITOR (-m, ksh: -m)
     Allow job control.  Set by default in interactive shells.

NOTIFY (-5, ksh: -b) <Z>
     Report the status of background jobs immediately, rather than
     waiting until just before printing a prompt.

POSIX_JOBS <K> <S>
     This option makes job control more compliant with the POSIX
     standard.

     When the option is not set, the MONITOR option is unset on entry to
     subshells, so that job control is no longer active.  When the
     option is set, the MONITOR option and job control remain active in
     the subshell, but note that the subshell has no access to jobs in
     the parent shell.

     When the option is not set, jobs put in the background or
     foreground with bg or fg are displayed with the same information
     that would be reported by jobs.  When the option is set, only the
     text is printed.  The output from jobs itself is not affected by
     the option.

     When the option is not set, job information from the parent shell
     is saved for output within a subshell (for example, within a
     pipeline).  When the option is set, the output of jobs is empty
     until a job is started within the subshell.

     When the option is set, it becomes possible to use the wait
     builtin to wait for the last job started in the background (as
     given by $!) even if that job has already exited.  This works even
     if the option is turned on temporarily around the use of the wait
     builtin.



16.2.8 Prompting
----------------


PROMPT_BANG <K>
     If set, `!' is treated specially in prompt expansion.  See *note
     Prompt Expansion::.

PROMPT_CR (+V) <D>
     Print a carriage return just before printing a prompt in the line
     editor.  This is on by default as multi-line editing is only
     possible if the editor knows where the start of the line appears.

PROMPT_SP <D>
     Attempt to preserve a partial line (i.e. a line that did not end
     with a newline) that would otherwise be covered up by the command
     prompt due to the PROMPT_CR option.  This works by outputting some
     cursor-control characters, including a series of spaces, that
     should make the terminal wrap to the next line when a partial line
     is present (note that this is only successful if your terminal has
     automatic margins, which is typical).

     When a partial line is preserved, by default you will see an
     inverse+bold character at the end of the partial line:  a "%" for
     a normal user or a "#" for root.  If set, the shell parameter
     PROMPT_EOL_MARK can be used to customize how the end of partial
     lines are shown.

     NOTE: if the PROMPT_CR option is not set, enabling this option will
     have no effect.  This option is on by default.

PROMPT_PERCENT <C> <Z>
     If set, `%' is treated specially in prompt expansion.  See *note
     Prompt Expansion::.

PROMPT_SUBST <K> <S>
     If set, _parameter expansion_, _command substitution_ and
     _arithmetic expansion_ are performed in prompts.  Substitutions
     within prompts do not affect the command status.

TRANSIENT_RPROMPT
     Remove any right prompt from display when accepting a command
     line.  This may be useful with terminals with other cut/paste
     methods.



16.2.9 Scripts and Functions
----------------------------


C_BASES
     Output hexadecimal numbers in the standard C format, for example
     `0xFF' instead of the usual `16#FF'.  If the option OCTAL_ZEROES
     is also set (it is not by default), octal numbers will be treated
     similarly and hence appear as `077' instead of `8#77'.  This
     option has no effect on the choice of the output base, nor on the
     output of bases other than hexadecimal and octal.  Note that these
     formats will be understood on input irrespective of the setting of
     C_BASES.

C_PRECEDENCES
     This alters the precedence of arithmetic operators to be more like
     C and other programming languages; Arithmetic Evaluation has an
     explicit list.

DEBUG_BEFORE_CMD
     Run the DEBUG trap before each command; otherwise it is run after
     each command.  Setting this option mimics the behaviour of ksh 93;
     with the option unset the behaviour is that of ksh 88.

ERR_EXIT (-e, ksh: -e)
     If a command has a non-zero exit status, execute the ZERR trap, if
     set, and exit.  This is disabled while running initialization
     scripts.

     The behaviour is also disabled inside DEBUG traps.  In this case
     the option is handled specially: it is unset on entry to the trap.
     If the option DEBUG_BEFORE_CMD is set, as it is by default, and
     the option ERR_EXIT is found to have been set on exit, then the
     command for which the DEBUG trap is being executed is skipped.
     The option is restored after the trap exits.

ERR_RETURN
     If a command has a non-zero exit status, return immediately from
     the enclosing function.  The logic is identical to that for
     ERR_EXIT, except that an implicit return statement is executed
     instead of an exit.  This will trigger an exit at the outermost
     level of a non-interactive script.

EVAL_LINENO <Z>
     If set, line numbers of expressions evaluated using the builtin
     eval are tracked separately of the enclosing environment.  This
     applies both to the parameter LINENO and the line number output by
     the prompt escape %i.  If the option is set, the prompt escape %N
     will output the string `(eval)' instead of the script or function
     name as an indication.   (The two prompt escapes are typically
     used in the parameter PS4 to be output when the option XTRACE is
     set.)  If EVAL_LINENO is unset, the line number of the surrounding
     script or function is retained during the evaluation.

EXEC (+n, ksh: +n) <D>
     Do execute commands.  Without this option, commands are read and
     checked for syntax errors, but not executed.  This option cannot
     be turned off in an interactive shell, except when `-n' is
     supplied to the shell at startup.

FUNCTION_ARGZERO <C> <Z>
     When executing a shell function or sourcing a script, set $0
     temporarily to the name of the function/script.

LOCAL_OPTIONS <K>
     If this option is set at the point of return from a shell function,
     most options (including this one) which were in force upon entry to
     the function are restored; options that are not restored are
     PRIVILEGED and RESTRICTED.  Otherwise, only this option and the
     XTRACE and PRINT_EXIT_VALUE options are restored.  Hence if this
     is explicitly unset by a shell function the other options in force
     at the point of return will remain so.  A shell function can also
     guarantee itself a known shell configuration with a formulation
     like `emulate -L zsh'; the -L activates LOCAL_OPTIONS.

LOCAL_TRAPS <K>
     If this option is set when a signal trap is set inside a function,
     then the previous status of the trap for that signal will be
     restored when the function exits.  Note that this option must be
     set _prior_ to altering the trap behaviour in a function; unlike
     LOCAL_OPTIONS, the value on exit from the function is irrelevant.
     However, it does not need to be set before any global trap for
     that to be correctly restored by a function.  For example,


          unsetopt localtraps
          trap - INT
          fn() { setopt localtraps; trap '' INT; sleep 3; }

     will restore normal handling of SIGINT after the function exits.

MULTI_FUNC_DEF <Z>
     Allow definitions of multiple functions at once in the form `fn1
     fn2...()'; if the option is not set, this causes a parse error.
     Definition of multiple functions with the function keyword is
     always allowed.  Multiple function definitions are not often used
     and can cause obscure errors.

MULTIOS <Z>
     Perform implicit `tee's or `cat's when multiple redirections are
     attempted (see *note Redirection::).

OCTAL_ZEROES <S>
     Interpret any integer constant beginning with a 0 as octal, per
     IEEE Std 1003.2-1992 (ISO 9945-2:1993).  This is not enabled by
     default as it causes problems with parsing of, for example, date
     and time strings with leading zeroes.

     Sequences of digits indicating a numeric base such as the `08'
     component in `08#77' are always interpreted as decimal, regardless
     of leading zeroes.

SOURCE_TRACE
     If set, zsh will print an informational message announcing the
     name of each file it loads.  The format of the output is similar
     to that for the XTRACE option, with the message <sourcetrace>.  A
     file may be loaded by the shell itself when it starts up and shuts
     down (Startup/Shutdown Files) or by the use of the `source' and
     `dot' builtin commands.

TYPESET_SILENT
     If this is unset, executing any of the `typeset' family of
     commands with no options and a list of parameters that have no
     values to be assigned but already exist will display the value of
     the parameter.  If the option is set, they will only be shown when
     parameters are selected with the `-m' option.  The option `-p' is
     available whether or not the option is set.

VERBOSE (-v, ksh: -v)
     Print shell input lines as they are read.

XTRACE (-x, ksh: -x)
     Print commands and their arguments as they are executed.  The
     output is proceded by the value of $PS4, formatted as described in
     *note Prompt Expansion::.



16.2.10 Shell Emulation
-----------------------


BASH_REMATCH
     When set, matches performed with the =~ operator will set the
     BASH_REMATCH array variable, instead of the default MATCH and
     match variables.  The first element of the BASH_REMATCH array will
     contain the entire matched text and subsequent elements will
     contain extracted substrings.  This option makes more sense when
     KSH_ARRAYS is also set, so that the entire matched portion is
     stored at index 0 and the first substring is at index 1.  Without
     this option, the MATCH variable contains the entire matched text
     and the match array variable contains substrings.

BSD_ECHO <S>
     Make the echo builtin compatible with the BSD man page echo(1)
     command.  This disables backslashed escape sequences in echo
     strings unless the -e option is specified.

CSH_JUNKIE_HISTORY <C>
     A history reference without an event specifier will always refer
     to the previous command.  Without this option, such a history
     reference refers to the same event as the previous history
     reference, defaulting to the previous command.

CSH_JUNKIE_LOOPS <C>
     Allow loop bodies to take the form `LIST; end' instead of `do
     LIST; done'.

CSH_JUNKIE_QUOTES <C>
     Changes the rules for single- and double-quoted text to match that
     of `csh'.  These require that embedded newlines be preceded by a
     backslash; unescaped newlines will cause an error message.  In
     double-quoted strings, it is made impossible to escape `$', ``' or
     `"' (and `\' itself no longer needs escaping).  Command
     substitutions are only expanded once, and cannot be nested.

CSH_NULLCMD <C>
     Do not use the values of NULLCMD and READNULLCMD when running
     redirections with no command.  This make such redirections fail
     (see *note Redirection::).

KSH_ARRAYS <K> <S>
     Emulate `ksh' array handling as closely as possible.  If this
     option is set, array elements are numbered from zero, an array
     parameter without subscript refers to the first element instead of
     the whole array, and braces are required to delimit a subscript
     (`${path[2]}' rather than just `$path[2]').

KSH_AUTOLOAD <K> <S>
     Emulate `ksh' function autoloading.  This means that when a
     function is autoloaded, the corresponding file is merely executed,
     and must define the function itself.  (By default, the function is
     defined to the contents of the file.  However, the most common
     `ksh'-style case - of the file containing only a simple definition
     of the function - is always handled in the `ksh'-compatible
     manner.)

KSH_OPTION_PRINT <K>
     Alters the way options settings are printed: instead of separate
     lists of set and unset options, all options are shown, marked `on'
     if they are in the non-default state, `off' otherwise.

KSH_TYPESET <K>
     Alters the way arguments to the typeset family of commands,
     including declare, export, float, integer, local and readonly, are
     processed.  Without this option, zsh will perform normal word
     splitting after command and parameter expansion in arguments of an
     assignment; with it, word splitting does not take place in those
     cases.

KSH_ZERO_SUBSCRIPT
     Treat use of a subscript of value zero in array or string
     expressions as a reference to the first element, i.e. the element
     that usually has the subscript 1.  Ignored if KSH_ARRAYS is also
     set.

     If neither this option nor KSH_ARRAYS is set, accesses to an
     element of an array or string with subscript zero return an empty
     element or string, while attempts to set element zero of an array
     or string are treated as an error.  However, attempts to set an
     otherwise valid subscript range that includes zero will succeed.
     For example, if KSH_ZERO_SUBSCRIPT is not set,


          array[0]=(element)

     is an error, while


          array[0,1]=(element)

     is not and will replace the first element of the array.

     This option is for compatibility with older versions of the shell
     and is not recommended in new code.

POSIX_ALIASES <K> <S>
     When this option is set, reserved words are not candidates for
     alias expansion:  it is still possible to declare any of them as
     an alias, but the alias will never be expanded.  Reserved words
     are described in *note Reserved Words::.

     Alias expansion takes place while text is being read; hence when
     this option is set it does not take effect until the end of any
     function or other piece of shell code parsed as one unit.  Note
     this may cause differences from other shells even when the option
     is in effect.  For example, when running a command with `zsh -c',
     or even `zsh -o posixaliases -c', the entire command argument is
     parsed as one unit, so aliases defined within the argument are not
     available even in later lines.  If in doubt, avoid use of aliases
     in non-interactive code.

POSIX_BUILTINS <K> <S>
     When this option is set the command builtin can be used to execute
     shell builtin commands.  Parameter assignments specified before
     shell functions and special builtins are kept after the command
     completes unless the special builtin is prefixed with the command
     builtin.  Special builtins are ., :, break, continue, declare,
     eval, exit, export, integer, local, readonly, return, set, shift,
     source, times, trap and unset.

POSIX_IDENTIFIERS <K> <S>
     When this option is set, only the ASCII characters a to z, A to Z,
     0 to 9 and _ may be used in identifiers (names of shell parameters
     and modules).

     When the option is unset and multibyte character support is
     enabled (i.e. it is compiled in and the option MULTIBYTE is set),
     then additionally any alphanumeric characters in the local
     character set may be used in identifiers.  Note that scripts and
     functions written with this feature are not portable, and also
     that both options must be set before the script or function is
     parsed; setting them during execution is not sufficient as the
     syntax VARIABLE=VALUE has already been parsed as a command rather
     than an assignment.

     If multibyte character support is not compiled into the shell this
     option is ignored; all octets with the top bit set may be used in
     identifiers.  This is non-standard but is the traditional zsh
     behaviour.

POSIX_STRINGS <K> <S>
     This option affects processing of quoted strings.  Currently it
     only affects the behaviour of null characters, i.e. character 0 in
     the portable character set corresponding to US ASCII.

     When this option is not set, null characters embedded within
     strings of the form $'...' are treated as ordinary characters. The
     entire string is maintained within the shell and output to files
     where necessary, although owing to restrictions of the library
     interface the string is truncated at the null character in file
     names, environment variables, or in arguments to external programs.

     When this option is set, the $'...' expression is truncated at the
     null character.  Note that remaining parts of the same string
     beyond the termination of the quotes are not trunctated.

     For example, the command line argument a$'b\0c'd is treated with
     the option off as the characters a, b, null, c, d, and with the
     option on as the characters a, b, d.

POSIX_TRAPS <K> <S>
     When the is option is set, the usual zsh behaviour of executing
     traps for EXIT on exit from shell functions is suppressed.  In
     that case, manipulating EXIT traps always alters the global trap
     for exiting the shell; the LOCAL_TRAPS option is ignored for the
     EXIT trap.

SH_FILE_EXPANSION <K> <S>
     Perform filename expansion (e.g., ~ expansion) _before_ parameter
     expansion, command substitution, arithmetic expansion and brace
     expansion.  If this option is unset, it is performed _after_ brace
     expansion, so things like `~$USERNAME' and `~{pfalstad,rc}' will
     work.

SH_NULLCMD <K> <S>
     Do not use the values of NULLCMD and READNULLCMD when doing
     redirections, use `:' instead (see *note Redirection::).

SH_OPTION_LETTERS <K> <S>
     If this option is set the shell tries to interpret single letter
     options (which are used with set and setopt) like `ksh' does.
     This also affects the value of the - special parameter.

SH_WORD_SPLIT (-y) <K> <S>
     Causes field splitting to be performed on unquoted parameter
     expansions.  Note that this option has nothing to do with word
     splitting.  (See *note Parameter Expansion::.)

TRAPS_ASYNC
     While waiting for a program to exit, handle signals and run traps
     immediately.  Otherwise the trap is run after a child process has
     exited.  Note this does not affect the point at which traps are
     run for any case other than when the shell is waiting for a child
     process.



16.2.11 Shell State
-------------------


INTERACTIVE (-i, ksh: -i)
     This is an interactive shell.  This option is set upon
     initialisation if the standard input is a tty and commands are
     being read from standard input.  (See the discussion of
     SHIN_STDIN.)  This heuristic may be overridden by specifying a
     state for this option on the command line.  The value of this
     option can only be changed via flags supplied at invocation of the
     shell.  It cannot be changed once zsh is running.

LOGIN (-l, ksh: -l)
     This is a login shell.  If this option is not explicitly set, the
     shell is a login shell if the first character of the argv[0]
     passed to the shell is a `-'.

PRIVILEGED (-p, ksh: -p)
     Turn on privileged mode. This is enabled automatically on startup
     if the effective user (group) ID is not equal to the real user
     (group) ID.  Turning this option off causes the effective user and
     group IDs to be set to the real user and group IDs. This option
     disables sourcing user startup files.  If zsh is invoked as `sh'
     or `ksh' with this option set, /etc/suid_profile is sourced (after
     /etc/profile on interactive shells). Sourcing ~/.profile is
     disabled and the contents of the ENV variable is ignored. This
     option cannot be changed using the -m option of setopt and
     unsetopt, and changing it inside a function always changes it
     globally regardless of the LOCAL_OPTIONS option.

RESTRICTED (-r)
     Enables restricted mode.  This option cannot be changed using
     unsetopt, and setting it inside a function always changes it
     globally regardless of the LOCAL_OPTIONS option.  See *note
     Restricted Shell::.

SHIN_STDIN (-s, ksh: -s)
     Commands are being read from the standard input.  Commands are
     read from standard input if no command is specified with -c and no
     file of commands is specified.  If SHIN_STDIN is set explicitly on
     the command line, any argument that would otherwise have been
     taken as a file to run will instead be treated as a normal
     positional parameter.  Note that setting or unsetting this option
     on the command line does not necessarily affect the state the
     option will have while the shell is running - that is purely an
     indicator of whether on not commands are _actually_ being read
     from standard input.  The value of this option can only be changed
     via flags supplied at invocation of the shell.  It cannot be
     changed once zsh is running.

SINGLE_COMMAND (-t, ksh: -t)
     If the shell is reading from standard input, it exits after a
     single command has been executed.  This also makes the shell
     non-interactive, unless the INTERACTIVE option is explicitly set
     on the command line.  The value of this option can only be changed
     via flags supplied at invocation of the shell.  It cannot be
     changed once zsh is running.



16.2.12 Zle
-----------


BEEP (+B) <D>
     Beep on error in ZLE.

COMBINING_CHARS
     Assume that the terminal displays combining characters correctly.
     Specifically, if a base alphanumeric character is followed by one
     or more zero-width punctuation characters, assume that the
     zero-width characters will be displayed as modifications to the
     base character within the same width.  Not all terminals handle
     this.  If this option is not set, zero-width characters are
     displayed separately with special mark-up.

     If this option is set, the pattern test [[:WORD:]] matches a
     zero-width punctuation character on the assumption that it will be
     used as part of a word in combination with a word character.
     Otherwise the base shell does not handle combining characters
     specially.

EMACS
     If ZLE is loaded, turning on this option has the equivalent effect
     of `bindkey -e'.  In addition, the VI option is unset.  Turning it
     off has no effect.  The option setting is not guaranteed to
     reflect the current keymap.  This option is provided for
     compatibility; bindkey is the recommended interface.

OVERSTRIKE
     Start up the line editor in overstrike mode.

SINGLE_LINE_ZLE (-M) <K>
     Use single-line command line editing instead of multi-line.

     Note that although this is on by default in ksh emulation it only
     provides superficial compatibility with the ksh line editor and
     reduces the effectiveness of the zsh line editor.  As it has no
     effect on shell syntax, many users may wish to disable this option
     when using ksh emulation interactively.

VI
     If ZLE is loaded, turning on this option has the equivalent effect
     of `bindkey -v'.  In addition, the EMACS option is unset.  Turning
     it off has no effect.  The option setting is not guaranteed to
     reflect the current keymap.  This option is provided for
     compatibility; bindkey is the recommended interface.

ZLE (-Z)
     Use the zsh line editor.  Set by default in interactive shells
     connected to a terminal.



File: zsh.info,  Node: Option Aliases,  Next: Single Letter Options,  Prev: Description of Options,  Up: Options

16.3 Option Aliases
===================

Some options have alternative names.  These aliases are never used for
output, but can be used just like normal option names when specifying
options to the shell.


BRACE_EXPAND
     _NO__IGNORE_BRACES (ksh and bash compatibility)

DOT_GLOB
     GLOB_DOTS (bash compatibility)

HASH_ALL
     HASH_CMDS (bash compatibility)

HIST_APPEND
     APPEND_HISTORY (bash compatibility)

HIST_EXPAND
     BANG_HIST (bash compatibility)

LOG
     _NO__HIST_NO_FUNCTIONS (ksh compatibility)

MAIL_WARN
     MAIL_WARNING (bash compatibility)

ONE_CMD
     SINGLE_COMMAND (bash compatibility)

PHYSICAL
     CHASE_LINKS (ksh and bash compatibility)

PROMPT_VARS
     PROMPT_SUBST (bash compatibility)

STDIN
     SHIN_STDIN (ksh compatibility)

TRACK_ALL
     HASH_CMDS (ksh compatibility)


File: zsh.info,  Node: Single Letter Options,  Prev: Option Aliases,  Up: Options

16.4 Single Letter Options
==========================



16.4.1 Default set
------------------


-0
     CORRECT

-1
     PRINT_EXIT_VALUE

-2
     _NO__BAD_PATTERN

-3
     _NO__NOMATCH

-4
     GLOB_DOTS

-5
     NOTIFY

-6
     BG_NICE

-7
     IGNORE_EOF

-8
     MARK_DIRS

-9
     AUTO_LIST

-B
     _NO__BEEP

-C
     _NO__CLOBBER

-D
     PUSHD_TO_HOME

-E
     PUSHD_SILENT

-F
     _NO__GLOB

-G
     NULL_GLOB

-H
     RM_STAR_SILENT

-I
     IGNORE_BRACES

-J
     AUTO_CD

-K
     _NO__BANG_HIST

-L
     SUN_KEYBOARD_HACK

-M
     SINGLE_LINE_ZLE

-N
     AUTO_PUSHD

-O
     CORRECT_ALL

-P
     RC_EXPAND_PARAM

-Q
     PATH_DIRS

-R
     LONG_LIST_JOBS

-S
     REC_EXACT

-T
     CDABLE_VARS

-U
     MAIL_WARNING

-V
     _NO__PROMPT_CR

-W
     AUTO_RESUME

-X
     LIST_TYPES

-Y
     MENU_COMPLETE

-Z
     ZLE

-a
     ALL_EXPORT

-e
     ERR_EXIT

-f
     _NO__RCS

-g
     HIST_IGNORE_SPACE

-h
     HIST_IGNORE_DUPS

-i
     INTERACTIVE

-k
     INTERACTIVE_COMMENTS

-l
     LOGIN

-m
     MONITOR

-n
     _NO__EXEC

-p
     PRIVILEGED

-r
     RESTRICTED

-s
     SHIN_STDIN

-t
     SINGLE_COMMAND

-u
     _NO__UNSET

-v
     VERBOSE

-w
     CHASE_LINKS

-x
     XTRACE

-y
     SH_WORD_SPLIT

16.4.2 sh/ksh emulation set
---------------------------


-C
     _NO__CLOBBER

-T
     TRAPS_ASYNC

-X
     MARK_DIRS

-a
     ALL_EXPORT

-b
     NOTIFY

-e
     ERR_EXIT

-f
     _NO__GLOB

-i
     INTERACTIVE

-l
     LOGIN

-m
     MONITOR

-n
     _NO__EXEC

-p
     PRIVILEGED

-r
     RESTRICTED

-s
     SHIN_STDIN

-t
     SINGLE_COMMAND

-u
     _NO__UNSET

-v
     VERBOSE

-x
     XTRACE

16.4.3 Also note
----------------


-A
     Used by set for setting arrays

-b
     Used on the command line to specify end of option processing

-c
     Used on the command line to specify a single command

-m
     Used by setopt for pattern-matching option setting

-o
     Used in all places to allow use of long option names

-s
     Used by set to sort positional parameters

File: zsh.info,  Node: Shell Builtin Commands,  Next: Zsh Line Editor,  Prev: Options,  Up: Top

17 Shell Builtin Commands
*************************


- SIMPLE COMMAND
     See *note Precommand Modifiers::.

. FILE [ ARG ... ]
     Read commands from FILE and execute them in the current shell
     environment.

     If FILE does not contain a slash, or if PATH_DIRS is set, the
     shell looks in the components of $path to find the directory
     containing FILE.  Files in the current directory are not read
     unless `.' appears somewhere in $path.  If a file named `FILE.zwc'
     is found, is newer than FILE, and is the compiled form (created
     with the zcompile builtin) of FILE, then commands are read from
     that file instead of FILE.

     If any arguments ARG are given, they become the positional
     parameters; the old positional parameters are restored when the
     FILE is done executing.  If FILE was not found the return status
     is 127; if FILE was found but contained a syntax error the return
     status is 126; else the return status is the exit status of the
     last command executed.

: [ ARG ... ]
     This command does nothing, although normal argument expansions is
     performed which may have effects on shell parameters.  A zero exit
     status is returned.

alias [ {+|-}gmrsL ] [ NAME[=VALUE] ... ]
     For each NAME with a corresponding VALUE, define an alias with
     that value.  A trailing space in VALUE causes the next word to be
     checked for alias expansion.  If the -g flag is present, define a
     global alias; global aliases are expanded even if they do not
     occur in command position.

     If the -s flags is present, define a suffix alias: if the command
     word on a command line is in the form `TEXT.NAME', where TEXT is
     any non-empty string, it is replaced by the text `VALUE
     TEXT.NAME'.  Note that NAME is treated as a literal string, not a
     pattern.  A trailing space in VALUE is not special in this case.
     For example,


          alias -s ps=gv

     will cause the command `*.ps' to be expanded to `gv *.ps'.  As
     alias expansion is carried out earlier than globbing, the `*.ps'
     will then be expanded.  Suffix aliases constitute a different name
     space from other aliases (so in the above example it is still
     possible to create an alias for the command ps) and the two sets
     are never listed together.

     For each NAME with no VALUE, print the value of NAME, if any.
     With no arguments, print all currently defined aliases other than
     suffix aliases.  If the -m flag is given the arguments are taken
     as patterns (they should be quoted to preserve them from being
     interpreted as glob patterns), and the aliases matching these
     patterns are printed.  When printing aliases and one of the -g, -r
     or -s flags is present, restrict the printing to global, regular
     or suffix aliases, respectively; a regular alias is one which is
     neither a global nor a suffix alias.   Using `+' instead of `-',
     or ending the option list with a single `+', prevents the values
     of the aliases from being printed.

     If the -L flag is present, then print each alias in a manner
     suitable for putting in a startup script.  The exit status is
     nonzero if a NAME (with no VALUE) is given for which no alias has
     been defined.

     For more on aliases, include common problems, *note Aliasing::.

autoload [ {+|-}UXktz ] [ -w ] [ NAME ... ]
     Equivalent to functions -u, with the exception of -X/+X and -w.

     The flag -X may be used only inside a shell function, and may not
     be followed by a NAME.  It causes the calling function to be
     marked for autoloading and then immediately loaded and executed,
     with the current array of positional parameters as arguments.
     This replaces the previous definition of the function.  If no
     function definition is found, an error is printed and the function
     remains undefined and marked for autoloading.

     The flag +X attempts to load each NAME as an autoloaded function,
     but does _not_ execute it.  The exit status is zero (success) if
     the function was not previously defined _and_ a definition for it
     was found.  This does _not_ replace any existing definition of the
     function.  The exit status is nonzero (failure) if the function
     was already defined or when no definition was found.  In the
     latter case the function remains undefined and marked for
     autoloading.  If ksh-style autoloading is enabled, the function
     created will contain the contents of the file plus a call to the
     function itself appended to it, thus giving normal ksh autoloading
     behaviour on the first call to the function.

     With the -w flag, the NAMEs are taken as names of files compiled
     with the zcompile builtin, and all functions defined in them are
     marked for autoloading.

     The flags -z and -k mark the function to be autoloaded in native
     or ksh emulation, as if the option KSH_AUTOLOAD were unset or were
     set, respectively.  The flags override the setting of the option
     at the time the function is loaded.

bg [ JOB ... ]
JOB ... &
     Put each specified JOB in the background, or the current job if
     none is specified.

bindkey
     See *note Zle Builtins::.

break [ N ]
     Exit from an enclosing for, while, until, select or repeat loop.
     If N is specified, then break N levels instead of just one.

builtin NAME [ ARGS ... ]
     Executes the builtin NAME, with the given ARGS.

bye
     Same as exit.

cap
     See *note The zsh/cap Module::.

cd [ -qsLP ] [ ARG ]
cd [ -qsLP ] OLD NEW
cd [ -qsLP ] {+|-}N
     Change the current directory.  In the first form, change the
     current directory to ARG, or to the value of $HOME if ARG is not
     specified.  If ARG is `-', change to the previous directory.

     Otherwise, if ARG begins with a slash, attempt to change to the
     directory given by ARG.

     If ARG does not begin with a slash, the behaviour depends on
     whether the current directory `.' occurs in the list of
     directories contained in the shell parameter cdpath.  If it does
     not, first attempt to change to the directory ARG under the
     current directory, and if that fails but cdpath is set and
     contains at least one element attempt to change to the directory
     ARG under each component of cdpath in turn until successful.  If
     `.' occurs in cdpath, then cdpath is searched strictly in order so
     that `.' is only tried at the appropriate point.

     The order of testing cdpath is modified if the option POSIX_CD is
     set, as described in the documentation for the option.

     If no directory is found, the option CDABLE_VARS is set, and a
     parameter named ARG exists whose value begins with a slash, treat
     its value as the directory.  In that case, the parameter is added
     to the named directory hash table.

     The second form of cd substitutes the string NEW for the string
     OLD in the name of the current directory, and tries to change to
     this new directory.

     The third form of cd extracts an entry from the directory stack,
     and changes to that directory.  An argument of the form `+N'
     identifies a stack entry by counting from the left of the list
     shown by the dirs command, starting with zero.  An argument of the
     form `-N' counts from the right.  If the PUSHD_MINUS option is
     set, the meanings of `+' and `-' in this context are swapped.

     If the -q (quiet) option is specified, the hook function chpwd and
     the functions in the array chpwd_functions are not called.  This
     is useful for calls to cd that do not change the environment seen
     by an interactive user.

     If the -s option is specified, cd refuses to change the current
     directory if the given pathname contains symlinks.  If the -P
     option is given or the CHASE_LINKS option is set, symbolic links
     are resolved to their true values.  If the -L option is given
     symbolic links are retained in the directory (and not resolved)
     regardless of the state of the CHASE_LINKS option.

chdir
     Same as cd.

clone
     See *note The zsh/clone Module::.

command [ -pvV ] SIMPLE COMMAND
     The simple command argument is taken as an external command
     instead of a function or builtin and is executed. If the
     POSIX_BUILTINS option is set, builtins will also be executed but
     certain special properties of them are suppressed. The -p flag
     causes a default path to be searched instead of that in $path.
     With the -v flag, command is similar to whence and with -V, it is
     equivalent to whence -v.

     See also *note Precommand Modifiers::.

comparguments
     See *note The zsh/computil Module::.

compcall
     See *note The zsh/compctl Module::.

compctl
     See *note The zsh/compctl Module::.

compdescribe
     See *note The zsh/computil Module::.

compfiles
     See *note The zsh/computil Module::.

compgroups
     See *note The zsh/computil Module::.

compquote
     See *note The zsh/computil Module::.

comptags
     See *note The zsh/computil Module::.

comptry
     See *note The zsh/computil Module::.

compvalues
     See *note The zsh/computil Module::.

continue [ N ]
     Resume the next iteration of the enclosing for, while, until,
     select or repeat loop.  If N is specified, break out of N-1 loops
     and resume at the Nth enclosing loop.

declare
     Same as typeset.

dirs [ -c ] [ ARG ... ]
dirs [ -lpv ]
     With no arguments, print the contents of the directory stack.
     Directories are added to this stack with the pushd command, and
     removed with the cd or popd commands.  If arguments are specified,
     load them onto the directory stack, replacing anything that was
     there, and push the current directory onto the stack.


    -c
          clear the directory stack.

    -l
          print directory names in full instead of using of using ~
          expressions.

    -p
          print directory entries one per line.

    -v
          number the directories in the stack when printing.



disable [ -afmrs ] NAME ...
     Temporarily disable the NAMEd hash table elements.  The default is
     to disable builtin commands.  This allows you to use an external
     command with the same name as a builtin command.  The -a option
     causes disable to act on regular or global aliases.  The -s option
     causes disable to act on suffix aliases.  The -f option causes
     disable to act on shell functions.  The -r options causes disable
     to act on reserved words.  Without arguments all disabled hash
     table elements from the corresponding hash table are printed.
     With the -m flag the arguments are taken as patterns (which should
     be quoted to prevent them from undergoing filename expansion), and
     all hash table elements from the corresponding hash table matching
     these patterns are disabled.  Disabled objects can be enabled with
     the enable command.

disown [ JOB ... ]
JOB ... &|
JOB ... &!
     Remove the specified JOBs from the job table; the shell will no
     longer report their status, and will not complain if you try to
     exit an interactive shell with them running or stopped.  If no JOB
     is specified, disown the current job.

     If the JOBs are currently stopped and the AUTO_CONTINUE option is
     not set, a warning is printed containing information about how to
     make them running after they have been disowned.  If one of the
     latter two forms is used, the JOBs will automatically be made
     running, independent of the setting of the AUTO_CONTINUE option.

echo [ -neE ] [ ARG ... ]
     Write each ARG on the standard output, with a space separating
     each one.  If the -n flag is not present, print a newline at the
     end.  echo recognizes the following escape sequences:


    \a
          bell character

    \b
          backspace

    \c
          suppress final newline

    \e
          escape

    \f
          form feed

    \n
          linefeed (newline)

    \r
          carriage return

    \t
          horizontal tab

    \v
          vertical tab

    \\
          backslash

    \0NNN
          character code in octal

    \xNN
          character code in hexadecimal

    \uNNNN
          unicode character code in hexadecimal

    \UNNNNNNNN
          unicode character code in hexadecimal

     The -E flag, or the BSD_ECHO option, can be used to disable these
     escape sequences.  In the latter case, -e flag can be used to
     enable them.

echotc
     See *note The zsh/termcap Module::.

echoti
     See *note The zsh/terminfo Module::.

emulate [ -LR ] [ {zsh|sh|ksh|csh} [ -c arg ] ]
     Without any argument print current emulation mode.

     With single argument set up zsh options to emulate the specified
     shell as much as possible.  `csh' will never be fully emulated.
     If the argument is not one of the shells listed above, zsh will be
     used as a default; more precisely, the tests performed on the
     argument are the same as those used to determine the emulation at
     startup based on the shell name, see *note Compatibility:: .

     If the -R option is given, all options are reset to their default
     value corresponding to the specified emulation mode, except for
     certain options describing the interactive environment; otherwise,
     only those options likely to cause portability problems in scripts
     and functions are altered.  If the -L option is given, the options
     LOCAL_OPTIONS and LOCAL_TRAPS will be set as well, causing the
     effects of the emulate command and any setopt and trap commands to
     be local to the immediately surrounding shell function, if any;
     normally these options are turned off in all emulation modes
     except ksh. The -L and -c are mutually exclusive.

     If -c arg is given, evaluate arg while the requested emulation is
     temporarily in effect.  The emulation and all options will be
     restored to their original values before emulate returns.  The -R
     flag may be used.

     Use of -c enables `sticky' emulation mode for functions defined
     within the evaluated expression:  the emulation mode is associated
     thereafter with the function so that whenever the function is
     executed the emulation (respecting the -R flag, if present) and all
     options are set before entry to the function, and restored after
     exit.  If the function is called when the sticky emulation is
     already in effect, either within an `emulate SHELL -c' expression
     or within another function with the same sticky emulation, entry
     and exit from the function do not cause options to be altered
     (except due to standard processing such as the LOCAL_OPTIONS
     option).

     For example:


          emulate sh -c 'fni() { setopt cshnullglob; }
          fno() { fni; }'
          fno

     The two functions fni and fno are defined with sticky sh
     emulation.  fno is then executed, causing options associated with
     emulations to be set to their values in sh.  fni then calls fno;
     because fno is also marked for sticky sh emulation, no option
     changes take place on entry to or exit from it.  Hence the option
     cshnullglob, turned off by sh emulation, will be turned on within
     fni and remain on on return to fno.  On exit from fno, the
     emulation mode and all options will be restored to the state they
     were in before entry to the temporary emulation.

     The documentation above is typically sufficient for the intended
     purpose of executing code designed for other shells in a suitable
     environment.  More detailed rules follow.
    1.
          The sticky emulation environment provided by `emulate SHELL
          -c' is identical to that provided by entry to a function
          marked for sticky emulation as a consequence of being defined
          in such an environment.  Hence, for example, the sticky
          emulation is inherited by subfunctions defined within
          functions with sticky emulation.

    2.
          No change of options takes place on entry to or exit from
          functions that are not marked for sticky emulation, other
          than those that would normally take place, even if those
          functions are called within sticky emulation.

    3.
          No special handling is provided for functions marked for
          autoload nor for functions present in wordcode created by the
          zcompile command.

    4.
          The presence or absence of the -R flag to emulate corresponds
          to different sticky emulation modes, so for example `emulate
          sh -c', `emulate -R sh -c' and `emulate csh -c' are treated
          as three distinct sticky emulations.

enable [ -afmrs ] NAME ...
     Enable the NAMEd hash table elements, presumably disabled earlier
     with disable.  The default is to enable builtin commands.  The -a
     option causes enable to act on regular or global aliases.  The -s
     option causes enable to act on suffix aliases.  The -f option
     causes enable to act on shell functions.  The -r option causes
     enable to act on reserved words.  Without arguments all enabled
     hash table elements from the corresponding hash table are printed.
     With the -m flag the arguments are taken as patterns (should be
     quoted) and all hash table elements from the corresponding hash
     table matching these patterns are enabled.  Enabled objects can be
     disabled with the disable builtin command.

eval [ ARG ... ]
     Read the arguments as input to the shell and execute the resulting
     command(s) in the current shell process.  The return status is the
     same as if the commands had been executed directly by the shell;
     if there are no ARGS or they contain no commands (i.e. are an
     empty string or whitespace) the return status is zero.

exec [ -cl ] [ -a ARGV0 ] SIMPLE COMMAND
     Replace the current shell with an external command rather than
     forking.  With -c clear the environment; with -l prepend - to the
     argv[0] string of the command executed (to simulate a login shell);
     with -a ARGV0 set the argv[0] string of the command executed.  See
     *note Precommand Modifiers::.

exit [ N ]
     Exit the shell with the exit status specified by N; if none is
     specified, use the exit status from the last command executed.  An
     EOF condition will also cause the shell to exit, unless the
     IGNORE_EOF option is set.

export [ NAME[=VALUE] ... ]
     The specified NAMEs are marked for automatic export to the
     environment of subsequently executed commands.  Equivalent to
     typeset -gx.  If a parameter specified does not already exist, it
     is created in the global scope.

false [ ARG ... ]
     Do nothing and return an exit status of 1.

fc [ -e ENAME ] [ -m MATCH ] [ OLD=NEW ... ] [ FIRST [ LAST ] ]
fc -l [ -nrdfEiD ] [ -t TIMEFMT ] [ -m MATCH ]
[ OLD=NEW ... ] [ FIRST [ LAST ] ]
fc -p [ -a ] [ FILENAME [ HISTSIZE [ SAVEHISTSIZE ] ] ]
fc -P
fc -ARWI [ FILENAME ]
     Select a range of commands from FIRST to LAST from the history
     list.  The arguments FIRST and LAST may be specified as a number
     or as a string.  A negative number is used as an offset to the
     current history event number.  A string specifies the most recent
     event beginning with the given string.  All substitutions OLD=NEW,
     if any, are then performed on the commands.

     If the -l flag is given, the resulting commands are listed on
     standard output.  If the -m flag is also given the first argument
     is taken as a pattern (should be quoted) and only the history
     events matching this pattern will be shown.  Otherwise the editor
     program ENAME is invoked on a file containing these history
     events.  If ENAME is not given, the value of the parameter FCEDIT
     is used; if that is not set the value of the parameter EDITOR is
     used; if that is not set a builtin default, usually `vi' is used.
     If ENAME is `-', no editor is invoked.  When editing is complete,
     the edited command is executed.

     If FIRST is not specified, it will be set to -1 (the most recent
     event), or to -16 if the -l flag is given.  If LAST is not
     specified, it will be set to FIRST, or to -1 if the -l flag is
     given.

     The flag -r reverses the order of the commands and the flag -n
     suppresses command numbers when listing.

     Also when listing,
    -d
          prints timestamps for each command

    -f
          prints full time-date stamps in the US `MM/DD/YY HH:MM' format

    -E
          prints full time-date stamps in the European `DD.MM.YYYY
          HH:MM' format

    -i
          prints full time-date stamps in ISO8601 `YYYY-MM-DD HH:MM'
          format

    -t FMT
          prints time and date stamps in the given format; FMT is
          formatted with the strftime function with the zsh extensions
          described for the %D{STRING} prompt format in *note Prompt
          Expansion::.  The resulting formatted string must be no more
          than 256 characters or will not be printed.

    -D
          prints elapsed times; may be combined with one of the options
          above.


     `fc -p' pushes the current history list onto a stack and switches
     to a new history list.  If the -a option is also specified, this
     history list will be automatically popped when the current
     function scope is exited, which is a much better solution than
     creating a trap function to call `fc -P' manually.  If no
     arguments are specified, the history list is left empty, $HISTFILE
     is unset, and $HISTSIZE & $SAVEHIST are set to their default
     values.  If one argument is given, $HISTFILE is set to that
     filename, $HISTSIZE & $SAVEHIST are left unchanged, and the history
     file is read in (if it exists) to initialize the new list.  If a
     second argument is specified, $HISTSIZE & $SAVEHIST are instead
     set to the single specified numeric value.  Finally, if a third
     argument is specified, $SAVEHIST is set to a separate value from
     $HISTSIZE.  You are free to change these environment values for
     the new history list however you desire in order to manipulate the
     new history list.

     `fc -P' pops the history list back to an older list saved by `fc
     -p'.  The current list is saved to its $HISTFILE before it is
     destroyed (assuming that $HISTFILE and $SAVEHIST are set
     appropriately, of course).  The values of $HISTFILE, $HISTSIZE,
     and $SAVEHIST are restored to the values they had when `fc -p' was
     called.  Note that this restoration can conflict with making these
     variables "local", so your best bet is to avoid local declarations
     for these variables in functions that use `fc -p'.  The one other
     guaranteed-safe combination is declaring these variables to be
     local at the top of your function and using the automatic option
     (-a) with `fc -p'.  Finally, note that it is legal to manually pop
     a push marked for automatic popping if you need to do so before the
     function exits.

     `fc -R' reads the history from the given file, `fc -W' writes the
     history out to the given file, and `fc -A' appends the history out
     to the given file.  If no filename is specified, the $HISTFILE is
     assumed.  If the -I option is added to -R, only those events that
     are not already contained within the internal history list are
     added.  If the -I option is added to -A or -W, only those events
     that are new since last incremental append/write to the history
     file are appended/written.  In any case, the created file will
     have no more than $SAVEHIST entries.

fg [ JOB ... ]
JOB ...
     Bring each specified JOB in turn to the foreground.  If no JOB is
     specified, resume the current job.

float [ {+|-}EFHghlprtux ] [ -LRZ [ N ]] [ NAME[=VALUE] ... ]
     Equivalent to typeset -E, except that options irrelevant to
     floating point numbers are not permitted.

functions [ {+|-}UXkmtuz ] [ NAME ... ]
functions -M MATHFN [ MIN [ MAX [ SHELLFN ] ] ]
functions -M [ -m PATTERN ... ]
functions +M [ -m ] MATHFN
     Equivalent to typeset -f, with the exception of the -M option.
     Use of the -M option may not be combined with any of the options
     handled by typeset -f.

     functions -M MATHFN defines MATHFN as the name of a mathematical
     function recognised in all forms of arithmetical expressions; see
     *note Arithmetic Evaluation::.  By default MATHFN may take any
     number of comma-separated arguments.  If MIN is given, it must
     have exactly MIN args; if MIN and MAX are both given, it must have
     at least MIN and and at most MAX args.  MAX may be -1 to indicate
     that there is no upper limit.

     By default the function is implemented by a shell function of the
     same name; if SHELLFN is specified it gives the name of the
     corresponding shell function while MATHFN remains the name used in
     arithmetical expressions.  The name of the function in $0 is
     MATHFN (not SHELLFN as would usually be the case), provided the
     option FUNCTION_ARGZERO is in effect.  The positional parameters
     in the shell function correspond to the arguments of the
     mathematical function call.  The result of the last arithmetical
     expression evaluated inside the shell function (even if it is a
     form that normally only returns a status) gives the result of the
     mathematical function.

     functions -M with no arguments lists all such user-defined
     functions in the same form as a definition.  With the additional
     option -m and a list of arguments, all functions whose MATHFN
     matches one of the pattern arguments are listed.

     function +M removes the list of mathematical functions; with the
     additional option -m the arguments are treated as patterns and all
     functions whose mathfn matches the pattern are removed.  Note that
     the shell function implementing the behaviour is not removed
     (regardless of whether its name coincides with mathfn).

     For example, the following prints the cube of 3:


          zmath_cube() { (( $1 * $1 * $1 )) }
          functions -M cube 1 1 zmath_cube
          print $(( cube(3) ))

getcap
     See *note The zsh/cap Module::.

getln [ -AclneE ] NAME ...
     Read the top value from the buffer stack and put it in the shell
     parameter name.  Equivalent to read -zr.

getopts OPTSTRING NAME [ ARG ... ]
     Checks the ARGs for legal options.  If the ARGs are omitted, use
     the positional parameters.  A valid option argument begins with a
     `+' or a `-'.  An argument not beginning with a `+' or a `-', or
     the argument `--', ends the options.  Note that a single `-' is
     not considered a valid option argument.  OPTSTRING contains the
     letters that getopts recognizes.  If a letter is followed by a
     `:', that option requires an argument.  The options can be
     separated from the argument by blanks.

     Each time it is invoked, getopts places the option letter it finds
     in the shell parameter NAME, prepended with a `+' when ARG begins
     with a `+'.  The index of the next ARG is stored in OPTIND.  The
     option argument, if any, is stored in OPTARG.

     The first option to be examined may be changed by explicitly
     assigning to OPTIND.  OPTIND has an initial value of 1, and is
     normally reset to 1 upon exit from a shell function.  OPTARG is
     not reset and retains its value from the most recent call to
     getopts.  If either of OPTIND or OPTARG is explicitly unset, it
     remains unset, and the index or option argument is not stored.
     The option itself is still stored in NAME in this case.

     A leading `:' in OPTSTRING causes getopts to store the letter of
     any invalid option in OPTARG, and to set NAME to `?' for an
     unknown option and to `:' when a required argument is missing.
     Otherwise, getopts sets NAME to `?' and prints an error message
     when an option is invalid.  The exit status is nonzero when there
     are no more options.

hash [ -Ldfmrv ] [ NAME[=VALUE] ] ...
     hash can be used to directly modify the contents of the command
     hash table, and the named directory hash table.  Normally one would
     modify these tables by modifying one's PATH (for the command hash
     table) or by creating appropriate shell parameters (for the named
     directory hash table).  The choice of hash table to work on is
     determined by the -d option; without the option the command hash
     table is used, and with the option the named directory hash table
     is used.

     Given no arguments, and neither the -r or -f options, the selected
     hash table will be listed in full.

     The -r option causes the selected hash table to be emptied.  It
     will be subsequently rebuilt in the normal fashion.  The -f option
     causes the selected hash table to be fully rebuilt immediately.
     For the command hash table this hashes all the absolute
     directories in the PATH, and for the named directory hash table
     this adds all users' home directories.  These two options cannot
     be used with any arguments.

     The -m option causes the arguments to be taken as patterns (which
     should be quoted) and the elements of the hash table matching
     those patterns are printed.  This is the only way to display a
     limited selection of hash table elements.

     For each NAME with a corresponding VALUE, put `NAME' in the
     selected hash table, associating it with the pathname `VALUE'.  In
     the command hash table, this means that whenever `NAME' is used as
     a command argument, the shell will try to execute the file given
     by `VALUE'.  In the named directory hash table, this means that
     `VALUE' may be referred to as `~NAME'.

     For each NAME with no corresponding VALUE, attempt to add NAME to
     the hash table, checking what the appropriate value is in the
     normal manner for that hash table.  If an appropriate value can't
     be found, then the hash table will be unchanged.

     The -v option causes hash table entries to be listed as they are
     added by explicit specification.  If has no effect if used with -f.

     If the -L flag is present, then each hash table entry is printed in
     the form of a call to hash.

history
     Same as fc -l.

integer [ {+|-}Hghilprtux ] [ -LRZ [ N ]] [ NAME[=VALUE] ... ]
     Equivalent to typeset -i, except that options irrelevant to
     integers are not permitted.

jobs [ -dlprs ] [ JOB ... ]
jobs -Z STRING
     Lists information about each given job, or all jobs if JOB is
     omitted.  The -l flag lists process IDs, and the -p flag lists
     process groups.  If the -r flag is specified only running jobs
     will be listed and if the -s flag is given only stopped jobs are
     shown.  If the -d flag is given, the directory from which the job
     was started (which may not be the current directory of the job)
     will also be shown.

     The -Z option replaces the shell's argument and environment space
     with the given string, truncated if necessary to fit.  This will
     normally be visible in ps (man page ps(1)) listings.  This feature
     is typically used by daemons, to indicate their state.

kill [ -s SIGNAL_NAME | -n SIGNAL_NUMBER | -SIG ] JOB ...
kill -l [ SIG ... ]
     Sends either SIGTERM or the specified signal to the given jobs or
     processes.  Signals are given by number or by names, with or
     without the `SIG' prefix.  If the signal being sent is not `KILL'
     or `CONT', then the job will be sent a `CONT' signal if it is
     stopped.  The argument JOB can be the process ID of a job not in
     the job list.  In the second form, kill -l, if SIG is not
     specified the signal names are listed.  Otherwise, for each SIG
     that is a name, the corresponding signal number is listed.  For
     each SIG that is a signal number or a number representing the exit
     status of a process which was terminated or stopped by a signal
     the name of the signal is printed.

     On some systems, alternative signal names are allowed for a few
     signals.  Typical examples are SIGCHLD and SIGCLD or SIGPOLL and
     SIGIO, assuming they correspond to the same signal number.  kill
     -l will only list the preferred form, however kill -l ALT will
     show if the alternative form corresponds to a signal number.  For
     example, under Linux kill -l IO and kill -l POLL both output 29,
     hence kill -IO and kill -POLL have the same effect.

     Many systems will allow process IDs to be negative to kill a
     process group or zero to kill the current process group.

let ARG ...
     Evaluate each ARG as an arithmetic expression.  See *note
     Arithmetic Evaluation:: for a description of arithmetic
     expressions.  The exit status is 0 if the value of the last
     expression is nonzero, 1 if it is zero, and 2 if an error occurred.

limit [ -hs ] [ RESOURCE [ LIMIT ] ] ...
     Set or display resource limits.  Unless the -s flag is given, the
     limit applies only the children of the shell.  If -s is given
     without other arguments, the resource limits of the current shell
     is set to the previously set resource limits of the children.

     If LIMIT is not specified, print the current limit placed on
     RESOURCE, otherwise set the limit to the specified value.  If the
     -h flag is given, use hard limits instead of soft limits.  If no
     RESOURCE is given, print all limits.

     When looping over multiple resources, the shell will abort
     immediately if it detects a badly formed argument.  However, if it
     fails to set a limit for some other reason it will continue trying
     to set the remaining limits.

     RESOURCE can be one of:


    addressspace
          Maximum amount of address space used.

    aiomemorylocked
          Maximum amount of memory locked in RAM for AIO operations.

    aiooperations
          Maximum number of AIO operations.

    cachedthreads
          Maximum number of cached threads.

    coredumpsize
          Maximum size of a core dump.

    cputime
          Maximum CPU seconds per process.

    datasize
          Maximum data size (including stack) for each process.

    descriptors
          Maximum value for a file descriptor.

    filesize
          Largest single file allowed.

    maxproc
          Maximum number of processes.

    maxpthreads
          Maximum number of threads per process.

    memorylocked
          Maximum amount of memory locked in RAM.

    memoryuse
          Maximum resident set size.

    msgqueue
          Maximum number of bytes in POSIX message queues.

    resident
          Maximum resident set size.

    sigpending
          Maximum number of pending signals.

    sockbufsize
          Maximum size of all socket buffers.

    stacksize
          Maximum stack size for each process.

    vmemorysize
          Maximum amount of virtual memory.

     Which of these resource limits are available depends on the system.
     RESOURCE can be abbreviated to any unambiguous prefix.  It can
     also be an integer, which corresponds to the integer defined for
     the resource by the operating system.

     If argument corresponds to a number which is out of the range of
     the resources configured into the shell, the shell will try to
     read or write the limit anyway, and will report an error if this
     fails.  As the shell does not store such resources internally, an
     attempt to set the limit will fail unless the -s option is present.

     LIMIT is a number, with an optional scaling factor, as follows:


    Nh
          hours

    Nk
          kilobytes (default)

    Nm
          megabytes or minutes

    [MM:]SS
          minutes and seconds

     The limit command is not made available by default when the shell
     starts in a mode emulating another shell.  It can be made available
     with the command `zmodload -F zsh/rlimits b:limit'.

local [ {+|-}AEFHUahlprtux ] [ -LRZi [ N ]] [ NAME[=VALUE] ] ...
     Same as typeset, except that the options -g, and -f are not
     permitted.  In this case the -x option does not force the use of
     -g, i.e. exported variables will be local to functions.

log
     List all users currently logged in who are affected by the current
     setting of the watch parameter.

logout [ N ]
     Same as exit, except that it only works in a login shell.

noglob SIMPLE COMMAND
     See *note Precommand Modifiers::.

popd [ [-q] {+|-}N ]
     Remove an entry from the directory stack, and perform a cd to the
     new top directory.  With no argument, the current top entry is
     removed.  An argument of the form `+N' identifies a stack entry by
     counting from the left of the list shown by the dirs command,
     starting with zero.  An argument of the form -n counts from the
     right.  If the PUSHD_MINUS option is set, the meanings of `+' and
     `-' in this context are swapped.

     If the -q (quiet) option is specified, the hook function chpwd and
     the functions in the array $chpwd_functions are not called, and
     the new directory stack is not printed.  This is useful for calls
     to popd that do not change the environment seen by an interactive
     user.

print [ -abcDilmnNoOpPrsz ] [ -u N ] [ -f FORMAT ] [ -C COLS ]
[ -R [ -en ]] [ ARG ... ]
     With the `-f' option the arguments are printed as described by
     printf.  With no flags or with the flag `-', the arguments are
     printed on the standard output as described by echo, with the
     following differences: the escape sequence `\M-X' metafies the
     character X (sets the highest bit), `\C-X' produces a control
     character (`\C-@' and `\C-?' give the characters NUL and delete),
     and `\E' is a synonym for `\e'.  Finally, if not in an escape
     sequence, `\' escapes the following character and is not printed.


    -a
          Print arguments with the column incrementing first.  Only
          useful with the -c and -C options.

    -b
          Recognize all the escape sequences defined for the bindkey
          command, see *note Zle Builtins::.

    -c
          Print the arguments in columns.  Unless -a is also given,
          arguments are printed with the row incrementing first.

    -C COLS
          Print the arguments in COLS columns.  Unless -a is also given,
          arguments are printed with the row incrementing first.

    -D
          Treat the arguments as directory names, replacing prefixes
          with ~ expressions, as appropriate.

    -i
          If given together with -o or -O, sorting is performed
          case-independently.

    -l
          Print the arguments separated by newlines instead of spaces.

    -m
          Take the first argument as a pattern (should be quoted), and
          remove it from the argument list together with subsequent
          arguments that do not match this pattern.

    -n
          Do not add a newline to the output.

    -N
          Print the arguments separated and terminated by nulls.

    -o
          Print the arguments sorted in ascending order.

    -O
          Print the arguments sorted in descending order.

    -p
          Print the arguments to the input of the coprocess.

    -P
          Perform prompt expansion (see *note Prompt Expansion::).

    -r
          Ignore the escape conventions of echo.

    -R
          Emulate the BSD echo command, which does not process escape
          sequences unless the -e flag is given.  The -n flag
          suppresses the trailing newline.  Only the -e and -n flags
          are recognized after -R; all other arguments and options are
          printed.

    -s
          Place the results in the history list instead of on the
          standard output.

    -u N
          Print the arguments to file descriptor N.

    -z
          Push the arguments onto the editing buffer stack, separated
          by spaces.


     If any of `-m', `-o' or `-O' are used in combination with `-f' and
     there are no arguments (after the removal process in the case of
     `-m') then nothing is printed.

printf FORMAT [ ARG ... ]
     Print the arguments according to the format specification.
     Formatting rules are the same as used in C. The same escape
     sequences as for echo are recognised in the format. All C
     conversion specifications ending in one of csdiouxXeEfgGn are
     handled. In addition to this, `%b' can be used instead of `%s' to
     cause escape sequences in the argument to be recognised and `%q'
     can be used to quote the argument in such a way that allows it to
     be reused as shell input. With the numeric format specifiers, if
     the corresponding argument starts with a quote character, the
     numeric value of the following character is used as the number to
     print otherwise the argument is evaluated as an arithmetic
     expression. See *note Arithmetic Evaluation:: for a description of
     arithmetic expressions. With `%n', the corresponding argument is
     taken as an identifier which is created as an integer parameter.

     Normally, conversion specifications are applied to each argument
     in order but they can explicitly specify the Nth argument is to be
     used by replacing `%' by `%N$' and `*' by `*N$'.  It is
     recommended that you do not mix references of this explicit style
     with the normal style and the handling of such mixed styles may be
     subject to future change.

     If arguments remain unused after formatting, the format string is
     reused until all arguments have been consumed. With the print
     builtin, this can be suppressed by using the -r option. If more
     arguments are required by the format than have been specified, the
     behaviour is as if zero or an empty string had been specified as
     the argument.

pushd [ -qsLP ] [ ARG ]
pushd [ -qsLP ] OLD NEW
pushd [ -qsLP ] {+|-}N
     Change the current directory, and push the old current directory
     onto the directory stack.  In the first form, change the current
     directory to ARG.  If ARG is not specified, change to the second
     directory on the stack (that is, exchange the top two entries), or
     change to $HOME if the PUSHD_TO_HOME option is set or if there is
     only one entry on the stack.  Otherwise, ARG is interpreted as it
     would be by cd.  The meaning of OLD and NEW in the second form is
     also the same as for cd.

     The third form of pushd changes directory by rotating the
     directory list.  An argument of the form `+N' identifies a stack
     entry by counting from the left of the list shown by the dirs
     command, starting with zero.  An argument of the form `-N' counts
     from the right.  If the PUSHD_MINUS option is set, the meanings of
     `+' and `-' in this context are swapped.

     If the -q (quiet) option is specified, the hook function chpwd and
     the functions in the array $chpwd_functions are not called, and
     the new directory stack is not printed.  This is useful for calls
     to pushd that do not change the environment seen by an interactive
     user.

     If the option -q is not specified and the shell option PUSHD_SILENT
     is not set, the directory stack will be printed after a pushd is
     performed.

     The options -s, -L and -P have the same meanings as for the cd
     builtin.

pushln [ ARG ... ]
     Equivalent to print -nz.

pwd [ -rLP ]
     Print the absolute pathname of the current working directory.  If
     the -r or the -P flag is specified, or the CHASE_LINKS option is
     set and the -L flag is not given, the printed path will not
     contain symbolic links.

r
     Same as fc -e -.

read [ -rszpqAclneE ] [ -t [ NUM ] ] [ -k [ NUM ] ] [ -d DELIM ] [ -u N ] [ NAME[?PROMPT] ] [ NAME ...  ]
     Read one line and break it into fields using the characters in
     $IFS as separators, except as noted below.  The first field is
     assigned to the first NAME, the second field to the second NAME,
     etc., with leftover fields assigned to the last NAME.  If NAME is
     omitted then REPLY is used for scalars and reply for arrays.


    -r
          Raw mode: a `\' at the end of a line does not signify line
          continuation and backslashes in the line don't quote the
          following character and are not removed.

    -s
          Don't echo back characters if reading from the terminal.
          Currently does not work with the -q option.

    -q
          Read only one character from the terminal and set NAME to `y'
          if this character was `y' or `Y' and to `n' otherwise.  With
          this flag set the return status is zero only if the character
          was `y' or `Y'.  This option may be used with a timeout; if
          the read times out, or encounters end of file, status 2 is
          returned.  Input is read from the terminal unless one of -u
          or -p is present.  This option may also be used within zle
          widgets.

    -k [ NUM ]
          Read only one (or NUM) characters.  All are assigned to the
          first NAME, without word splitting.  This flag is ignored
          when -q is present.  Input is read from the terminal unless
          one of -u or -p is present.  This option may also be used
          within zle widgets.

          Note that despite the mnemonic `key' this option does read
          full characters, which may consist of multiple bytes if the
          option MULTIBYTE is set.

    -z
          Read one entry from the editor buffer stack and assign it to
          the first NAME, without word splitting.  Text is pushed onto
          the stack with `print -z' or with push-line from the line
          editor (see *note Zsh Line Editor::).  This flag is ignored
          when the -k or -q flags are present.

    -e
    -E
          The input read is printed (echoed) to the standard output.
          If the -e flag is used, no input is assigned to the
          parameters.

    -A
          The first NAME is taken as the name of an array and all words
          are assigned to it.

    -c
    -l
          These flags are allowed only if called inside a function used
          for completion (specified with the -K flag to compctl).  If
          the -c flag is given, the words of the current command are
          read. If the -l flag is given, the whole line is assigned as
          a scalar.  If both flags are present, -l is used and -c is
          ignored.

    -n
          Together with -c, the number of the word the cursor is on is
          read.  With -l, the index of the character the cursor is on is
          read.  Note that the command name is word number 1, not word
          0, and that when the cursor is at the end of the line, its
          character index is the length of the line plus one.

    -u N
          Input is read from file descriptor N.

    -p
          Input is read from the coprocess.

    -d DELIM
          Input is terminated by the first character of DELIM instead of
          by newline.

    -t [ NUM ]
          Test if input is available before attempting to read.  If NUM
          is present, it must begin with a digit and will be evaluated
          to give a number of seconds, which may be a floating point
          number; in this case the read times out if input is not
          available within this time.  If NUM is not present, it is
          taken to be zero, so that read returns immediately if no
          input is available.  If no input is available, return status
          1 and do not set any variables.

          This option is not available when reading from the editor
          buffer with -z, when called from within completion with -c or
          -l, with -q which clears the input queue before reading, or
          within zle where other mechanisms should be used to test for
          input.

          Note that read does not attempt to alter the input processing
          mode.  The default mode is canonical input, in which an
          entire line is read at a time, so usually `read -t' will not
          read anything until an entire line has been typed.  However,
          when reading from the terminal with -k input is processed one
          key at a time; in this case, only availability of the first
          character is tested, so that e.g. `read -t -k 2' can still
          block on the second character.  Use two instances of `read -t
          -k' if this is not what is wanted.


     If the first argument contains a `?', the remainder of this word
     is used as a PROMPT on standard error when the shell is
     interactive.

     The value (exit status) of read is 1 when an end-of-file is
     encountered, or when -c or -l is present and the command is not
     called from a compctl function, or as described for -q.  Otherwise
     the value is 0.

     The behavior of some combinations of the -k, -p, -q, -u and -z
     flags is undefined.  Presently -q cancels all the others, -p
     cancels -u, -k cancels -z, and otherwise -z cancels both -p and -u.

     The -c or -l flags cancel any and all of -kpquz.

readonly
     Same as typeset -r.

rehash
     Same as hash -r.

return [ N ]
     Causes a shell function or `.' script to return to the invoking
     script with the return status specified by N.  If N is omitted,
     the return status is that of the last command executed.

     If return was executed from a trap in a TRAPNAL function, the
     effect is different for zero and non-zero return status.  With zero
     status (or after an implicit return at the end of the trap), the
     shell will return to whatever it was previously processing; with a
     non-zero status, the shell will behave as interrupted except that
     the return status of the trap is retained.  Note that the numeric
     value of the signal which caused the trap is passed as the first
     argument, so the statement `return $((128+$1))' will return the
     same status as if the signal had not been trapped.

sched
     See *note The zsh/sched Module::.

set [ {+|-}OPTIONS | {+|-}o [ OPTION_NAME ] ] ... [ {+|-}A [ NAME ] ] [ ARG ... ]
     Set the options for the shell and/or set the positional
     parameters, or declare and set an array.  If the -s option is
     given, it causes the specified arguments to be sorted before
     assigning them to the positional parameters (or to the array NAME
     if -A is used).  With +s sort arguments in descending order.  For
     the meaning of the other flags, see *note Options::.  Flags may be
     specified by name using the -o option. If no option name is
     supplied with -o, the current option states are printed:  see the
     description of setopt below for more information on the format.
     With +o they are printed in a form that can be used as input to
     the shell.

     If the -A flag is specified, NAME is set to an array containing
     the given ARGs; if no NAME is specified, all arrays are printed
     together with their values.

     If +A is used and NAME is an array, the given arguments will
     replace the initial elements of that array; if no NAME is
     specified, all arrays are printed without their values.

     The behaviour of arguments after -A NAME or +A NAME depends on
     whether the option KSH_ARRAYS is set.  If it is not set, all
     arguments following NAME are treated as values for the array,
     regardless of their form.  If the option is set, normal option
     processing continues at that point; only regular arguments are
     treated as values for the array.  This means that


          set -A array -x -- foo

     sets array to `-x -- foo' if KSH_ARRAYS is not set, but sets the
     array to foo and turns on the option `-x' if it is set.

     If the -A flag is not present, but there are arguments beyond the
     options, the positional parameters are set.  If the option list
     (if any) is terminated by `--', and there are no further
     arguments, the positional parameters will be unset.

     If no arguments and no `--' are given, then the names and values of
     all parameters are printed on the standard output.  If the only
     argument is `+', the names of all parameters are printed.

     For historical reasons, `set -' is treated as `set +xv' and `set -
     ARGS' as `set +xv - ARGS' when in any other emulation mode than
     zsh's native mode.

     The sched builtin is not made available by default when the shell
     starts in a mode emulating another shell.  It can be made available
     with the command `zmodload -F zsh/sched b:sched'.

setcap
     See *note The zsh/cap Module::.

setopt [ {+|-}OPTIONS | {+|-}o OPTION_NAME ] [ NAME ... ]
     Set the options for the shell.  All options specified either with
     flags or by name are set.

     If no arguments are supplied, the names of all options currently
     set are printed.  The form is chosen so as to minimize the
     differences from the default options for the current emulation
     (the default emulation being native zsh, shown as <Z> in *note
     Description of Options::).  Options that are on by default for the
     emulation are shown with the prefix no only if they are off, while
     other options are shown without the prefix no and only if they are
     on.  In addition to options changed from the default state by the
     user, any options activated automatically by the shell (for
     example, SHIN_STDIN or INTERACTIVE) will be shown in the list.
     The format is further modified by the option KSH_OPTION_PRINT,
     however the rationale for choosing options with or without the no
     prefix remains the same in this case.

     If the -m flag is given the arguments are taken as patterns (which
     should be quoted to protect them from filename expansion), and all
     options with names matching these patterns are set.

shift [ N ] [ NAME ... ]
     The positional parameters ${N+1} ... are renamed to $1 ..., where
     N is an arithmetic expression that defaults to 1.  If any NAMEs
     are given then the arrays with these names are shifted instead of
     the positional parameters.

source FILE [ ARG ... ]
     Same as `.', except that the current directory is always searched
     and is always searched first, before directories in $path.

stat
     See *note The zsh/stat Module::.

suspend [ -f ]
     Suspend the execution of the shell (send it a SIGTSTP) until it
     receives a SIGCONT.  Unless the -f option is given, this will
     refuse to suspend a login shell.

test [ ARG ... ]
[ [ ARG ... ] ]
     Like the system version of test.  Added for compatibility; use
     conditional expressions instead (see *note Conditional
     Expressions::).  The main differences between the conditional
     expression syntax and the test and [ builtins are:  these commands
     are not handled syntactically, so for example an empty variable
     expansion may cause an argument to be omitted; syntax errors cause
     status 2 to be returned instead of a shell error; and arithmetic
     operators expect integer arguments rather than arithmetic
     expressions.

     The command attempts to implement POSIX and its extensions where
     these are specified.  Unfortunately there are intrinsic
     ambiguities in the syntax; in particular there is no distinction
     between test operators and strings that resemble them.  The
     standard attempts to resolve these for small numbers of arguments
     (up to four); for five or more arguments compatibility cannot be
     relied on.  Users are urged wherever possible to use the `[[' test
     syntax which does not have these ambiguities.

times
     Print the accumulated user and system times for the shell and for
     processes run from the shell.

trap [ ARG ] [ SIG ... ]
     ARG is a series of commands (usually quoted to protect it from
     immediate evaluation by the shell) to be read and executed when
     the shell receives any of the signals specified by one or more SIG
     args.  Each SIG can be given as a number, or as the name of a
     signal either with or without the string SIG in front (e.g. 1,
     HUP, and SIGHUP are all the same signal).

     If ARG is `-', then the specified signals are reset to their
     defaults, or, if no SIG args are present, all traps are reset.

     If ARG is an empty string, then the specified signals are ignored
     by the shell (and by the commands it invokes).

     If ARG is omitted but one or more SIG args are provided (i.e.  the
     first argument is a valid signal number or name), the effect is the
     same as if ARG had been specified as `-'.

     The trap command with no arguments prints a list of commands
     associated with each signal.

     If SIG is ZERR then ARG will be executed after each command with a
     nonzero exit status.  ERR is an alias for ZERR on systems that
     have no SIGERR signal (this is the usual case).

     If SIG is DEBUG then ARG will be executed before each command if
     the option DEBUG_BEFORE_CMD is set (as it is by default), else
     after each command.  Here, a `command' is what is described as a
     `sublist' in the shell grammar, see *note Simple Commands &
     Pipelines::.  If DEBUG_BEFORE_CMD is set various additional
     features are available.  First, it is possible to skip the next
     command by setting the option ERR_EXIT; see the description of the
     ERR_EXIT option in *note Description of Options::.  Also, the
     shell parameter ZSH_DEBUG_CMD is set to the string corresponding
     to the command to be executed following the trap.  Note that this
     string is reconstructed from the internal format and may not be
     formatted the same way as the original text.  The parameter is
     unset after the trap is executed.

     If SIG is 0 or EXIT and the trap statement is executed inside the
     body of a function, then the command ARG is executed after the
     function completes.  The value of $? at the start of execution is
     the exit status of the shell or the return status of the function
     exiting.  If SIG is 0 or EXIT and the trap statement is not
     executed inside the body of a function, then the command ARG is
     executed when the shell terminates; the trap runs before any
     zshexit hook functions.

     ZERR, DEBUG, and EXIT traps are not executed inside other traps.
     ZERR and DEBUG traps are kept within subshells, while other traps
     are reset.

     Note that traps defined with the trap builtin are slightly
     different from those defined as `TRAPNAL () { ... }', as the
     latter have their own function environment (line numbers, local
     variables, etc.) while the former use the environment of the
     command in which they were called.  For example,


          trap 'print $LINENO' DEBUG

     will print the line number of a command executed after it has run,
     while


          TRAPDEBUG() { print $LINENO; }

     will always print the number zero.

     Alternative signal names are allowed as described under kill above.
     Defining a trap under either name causes any trap under an
     alternative name to be removed.  However, it is recommended that
     for consistency users stick exclusively to one name or another.

true [ ARG ... ]
     Do nothing and return an exit status of 0.

ttyctl -fu
     The -f option freezes the tty, and -u unfreezes it.  When the tty
     is frozen, no changes made to the tty settings by external
     programs will be honored by the shell, except for changes in the
     size of the screen; the shell will simply reset the settings to
     their previous values as soon as each command exits or is
     suspended.  Thus, stty and similar programs have no effect when
     the tty is frozen.  Without options it reports whether the
     terminal is frozen or not.

type [ -wfpams ] NAME ...
     Equivalent to whence -v.

typeset [ {+|-}AEFHUafghklprtuxmz ] [ -LRZi [ N ]] [ NAME[=VALUE] ... ]
typeset -T [ {+|-}Urux ] [ -LRZ [ N ]] SCALAR[=VALUE] ARRAY [ SEP ]
     Set or display attributes and values for shell parameters.

     A parameter is created for each NAME that does not already refer
     to one.  When inside a function, a new parameter is created for
     every NAME (even those that already exist), and is unset again
     when the function completes.  See *note Local Parameters::.  The
     same rules apply to special shell parameters, which retain their
     special attributes when made local.

     For each NAME=VALUE assignment, the parameter NAME is set to
     VALUE.  Note that arrays currently cannot be assigned in typeset
     expressions, only scalars and integers.  Unless the option
     KSH_TYPESET is set, normal expansion rules apply to assignment
     arguments, so VALUE may be split into separate words; if the
     option is set, assignments which can be recognised when expansion
     is performed are treated as single words.  For example the command
     typeset vbl=$(echo one two) is treated as having one argument if
     KSH_TYPESET is set, but otherwise is treated as having the two
     arguments vbl=one and two.

     If the shell option TYPESET_SILENT is not set, for each remaining
     NAME that refers to a parameter that is set, the name and value of
     the parameter are printed in the form of an assignment.  Nothing
     is printed for newly-created parameters, or when any attribute
     flags listed below are given along with the NAME.  Using `+'
     instead of minus to introduce an attribute turns it off.

     If the -p option is given, parameters and values are printed in the
     form of a typeset command and an assignment (which will be printed
     separately for arrays and associative arrays), regardless of other
     flags and options.  Note that the -h flag on parameters is
     respected; no value will be shown for these parameters.

     If the -T option is given, two or three arguments must be present
     (an exception is that zero arguments are allowed to show the list
     of parameters created in this fashion).  The first two are the
     name of a scalar and an array parameter (in that order) that will
     be tied together in the manner of $PATH and $path.  The optional
     third argument is a single-character separator which will be used
     to join the elements of the array to form the scalar; if absent, a
     colon is used, as with $PATH.  Only the first character of the
     separator is significant; any remaining characters are ignored.
     Only the scalar parameter may be assigned an initial value.  Both
     the scalar and the array may otherwise be manipulated as normal.
     If one is unset, the other will automatically be unset too.  There
     is no way of untying the variables without unsetting them, or
     converting the type of one of them with another typeset command;
     +T does not work, assigning an array to SCALAR is an error, and
     assigning a scalar to ARRAY sets it to be a single-element array.
     Note that both `typeset -xT ...'  and `export -T ...' work, but
     only the scalar will be marked for export.  Setting the value
     using the scalar version causes a split on all separators (which
     cannot be quoted).

     The -g (global) flag is treated specially: it means that any
     resulting parameter will not be restricted to local scope.  Note
     that this does not necessarily mean that the parameter will be
     global, as the flag will apply to any existing parameter (even if
     unset) from an enclosing function.  This flag does not affect the
     parameter after creation, hence it has no effect when listing
     existing parameters, nor does the flag +g have any effect except
     in combination with -m (see below).

     If no NAME is present, the names and values of all parameters are
     printed.  In this case the attribute flags restrict the display to
     only those parameters that have the specified attributes, and
     using `+' rather than `-' to introduce the flag suppresses
     printing of the values of parameters when there is no parameter
     name.  Also, if the last option is the word `+', then names are
     printed but values are not.

     If the -m flag is given the NAME arguments are taken as patterns
     (which should be quoted).  With no attribute flags, all parameters
     (or functions with the -f flag) with matching names are printed
     (the shell option TYPESET_SILENT is not used in this case).  Note
     that -m is ignored if no patterns are given.  If the +g flag is
     combined with -m, a new local parameter is created for every
     matching parameter that is not already local.  Otherwise -m
     applies all other flags or assignments to the existing parameters.
     Except when assignments are made with NAME=VALUE, using +m forces
     the matching parameters to be printed, even inside a function.

     If no attribute flags are given and either no -m flag is present or
     the +m form was used, each parameter name printed is preceded by a
     list of the attributes of that parameter (array, association,
     exported, integer, readonly).  If +m is used with attribute flags,
     and all those flags are introduced with +, the matching parameter
     names are printed but their values are not.

     Attribute flags that transform the final value (-L, -R, -Z, -l, u)
     are only applied to the expanded value at the point of a parameter
     expansion expression using `$'.  They are not applied when a
     parameter is retrieved internally by the shell for any purpose.

     The following attribute flags may be specified:


    -A
          The names refer to associative array parameters; see *note
          Array Parameters::.

    -L
          Left justify and remove leading blanks from VALUE.  If N is
          nonzero, it defines the width of the field.  If N is zero,
          the width is determined by the width of the value of the
          first assignment.  In the case of numeric parameters, the
          length of the complete value assigned to the parameter is
          used to determine the width, not the value that would be
          output.

          The width is the count of characters, which may be multibyte
          characters if the MULTIBYTE option is in effect.  Note that
          the screen width of the character is not taken into account;
          if this is required, use padding with parameter expansion
          flags ${(ml...)...} as described in `Parameter Expansion
          Flags' in *note Parameter Expansion::.

          When the parameter is expanded, it is filled on the right with
          blanks or truncated if necessary to fit the field.  Note
          truncation can lead to unexpected results with numeric
          parameters.  Leading zeros are removed if the -Z flag is also
          set.

    -R
          Similar to -L, except that right justification is used; when
          the parameter is expanded, the field is left filled with
          blanks or truncated from the end.  May not be combined with
          the -Z flag.

    -U
          For arrays (but not for associative arrays), keep only the
          first occurrence of each duplicated value.  This may also be
          set for colon-separated special parameters like PATH or
          FIGNORE, etc.  This flag has a different meaning when used
          with -f; see below.

    -Z
          Specially handled if set along with the -L flag.  Otherwise,
          similar to -R, except that leading zeros are used for padding
          instead of blanks if the first non-blank character is a digit.
          Numeric parameters are specially handled: they are always
          eligible for padding with zeroes, and the zeroes are inserted
          at an appropriate place in the output.

    -a
          The names refer to array parameters.  An array parameter may
          be created this way, but it may not be assigned to in the
          typeset statement.  When displaying, both normal and
          associative arrays are shown.

    -f
          The names refer to functions rather than parameters.  No
          assignments can be made, and the only other valid flags are
          -t, -k, -u, -U and -z.  The flag -t turns on execution
          tracing for this function.  The -u and -U flags cause the
          function to be marked for autoloading; -U also causes alias
          expansion to be suppressed when the function is loaded.  The
          fpath parameter will be searched to find the function
          definition when the function is first referenced; see *note
          Functions::. The -k and -z flags make the function be loaded
          using ksh-style or zsh-style autoloading respectively. If
          neither is given, the setting of the KSH_AUTOLOAD option
          determines how the function is loaded.

    -h
          Hide: only useful for special parameters (those marked `<S>'
          in the table in *note Parameters Set By The Shell::), and for
          local parameters with the same name as a special parameter,
          though harmless for others.  A special parameter with this
          attribute will not retain its special effect when made local.
          Thus after `typeset -h PATH', a function containing `typeset
          PATH' will create an ordinary local parameter without the
          usual behaviour of PATH.  Alternatively, the local parameter
          may itself be given this attribute; hence inside a function
          `typeset -h PATH' creates an ordinary local parameter and the
          special PATH parameter is not altered in any way.  It is also
          possible to create a local parameter using `typeset +h
          SPECIAL', where the local copy of SPECIAL will retain its
          special properties regardless of having the -h attribute.
          Global special parameters loaded from shell modules
          (currently those in zsh/mapfile and zsh/parameter) are
          automatically given the -h attribute to avoid name clashes.

    -H
          Hide value: specifies that typeset will not display the value
          of the parameter when listing parameters; the display for
          such parameters is always as if the `+' flag had been given.
          Use of the parameter is in other respects normal, and the
          option does not apply if the parameter is specified by name,
          or by pattern with the -m option.  This is on by default for
          the parameters in the zsh/parameter and zsh/mapfile modules.
          Note, however, that unlike the -h flag this is also useful
          for non-special parameters.

    -i
          Use an internal integer representation.  If N is nonzero it
          defines the output arithmetic base, otherwise it is
          determined by the first assignment.  Bases from 2 to 36
          inclusive are allowed.

    -E
          Use an internal double-precision floating point
          representation.  On output the variable will be converted to
          scientific notation.  If N is nonzero it defines the number
          of significant figures to display; the default is ten.

    -F
          Use an internal double-precision floating point
          representation.  On output the variable will be converted to
          fixed-point decimal notation.  If N is nonzero it defines the
          number of digits to display after the decimal point; the
          default is ten.

    -l
          Convert the result to lower case whenever the parameter is
          expanded.  The value is _not_ converted when assigned.

    -r
          The given NAMEs are marked readonly.  Note that if NAME is a
          special parameter, the readonly attribute can be turned on,
          but cannot then be turned off.

    -t
          Tags the named parameters.  Tags have no special meaning to
          the shell.  This flag has a different meaning when used with
          -f; see above.

    -u
          Convert the result to upper case whenever the parameter is
          expanded.  The value is _not_ converted when assigned.  This
          flag has a different meaning when used with -f; see above.

    -x
          Mark for automatic export to the environment of subsequently
          executed commands.  If the option GLOBAL_EXPORT is set, this
          implies the option -g, unless +g is also explicitly given; in
          other words the parameter is not made local to the enclosing
          function.  This is for compatibility with previous versions
          of zsh.


ulimit [ [ -SHacdfilmnpqstvx | -N RESOURCE [ LIMIT ] ... ]
     Set or display resource limits of the shell and the processes
     started by the shell.  The value of LIMIT can be a number in the
     unit specified below or one of the values `unlimited', which
     removes the limit on the resource, or `hard', which uses the
     current value of the hard limit on the resource.

     By default, only soft limits are manipulated. If the -H flag is
     given use hard limits instead of soft limits.  If the -S flag is
     given together with the -H flag set both hard and soft limits.

     If no options are used, the file size limit (-f) is assumed.

     If LIMIT is omitted the current value of the specified resources
     are printed.  When more than one resource value is printed, the
     limit name and unit is printed before each value.

     When looping over multiple resources, the shell will abort
     immediately if it detects a badly formed argument.  However, if it
     fails to set a limit for some other reason it will continue trying
     to set the remaining limits.


    -a
          Lists all of the current resource limits.

    -c
          512-byte blocks on the size of core dumps.

    -d
          K-bytes on the size of the data segment.

    -f
          512-byte blocks on the size of files written.

    -i
          The number of pending signals.

    -l
          K-bytes on the size of locked-in memory.

    -m
          K-bytes on the size of physical memory.

    -n
          open file descriptors.

    -q
          Bytes in POSIX message queues.

    -s
          K-bytes on the size of the stack.

    -t
          CPU seconds to be used.

    -u
          processes available to the user.

    -v
          K-bytes on the size of virtual memory.  On some systems this
          refers to the limit called `address space'.

    -x
          The number of locks on files.

     A resource may also be specified by integer in the form `-N
     RESOURCE', where RESOURCE corresponds to the integer defined for
     the resource by the operating system.  This may be used to set the
     limits for resources known to the shell which do not correspond to
     option letters.  Such limits will be shown by number in the output
     of `ulimit -a'.

     The number may alternatively be out of the range of limits
     compiled into the shell.  The shell will try to read or write the
     limit anyway, and will report an error if this fails.

umask [ -S ] [ MASK ]
     The umask is set to MASK.  MASK can be either an octal number or a
     symbolic value as described in man page chmod(1).  If MASK is
     omitted, the current value is printed.  The -S option causes the
     mask to be printed as a symbolic value.  Otherwise, the mask is
     printed as an octal number.  Note that in the symbolic form the
     permissions you specify are those which are to be allowed (not
     denied) to the users specified.

unalias
     Same as unhash -a.

unfunction
     Same as unhash -f.

unhash [ -adfms ] NAME ...
     Remove the element named NAME from an internal hash table.  The
     default is remove elements from the command hash table.  The -a
     option causes unhash to remove regular or global aliases; note
     when removing a global aliases that the argument must be quoted to
     prevent it from being expanded before being passed to the command.
     The -s option causes unhash to remove suffix aliases.  The -f
     option causes unhash to remove shell functions.  The -d options
     causes unhash to remove named directories.  If the -m flag is given
     the arguments are taken as patterns (should be quoted) and all
     elements of the corresponding hash table with matching names will
     be removed.

unlimit [ -hs ] RESOURCE ...
     The resource limit for each RESOURCE is set to the hard limit.  If
     the -h flag is given and the shell has appropriate privileges, the
     hard resource limit for each RESOURCE is removed.  The resources
     of the shell process are only changed if the -s flag is given.

     The unlimit command is not made available by default when the
     shell starts in a mode emulating another shell.  It can be made
     available with the command `zmodload -F zsh/rlimits b:unlimit'.

unset [ -fmv ] NAME ...
     Each named parameter is unset.  Local parameters remain local even
     if unset; they appear unset within scope, but the previous value
     will still reappear when the scope ends.

     Individual elements of associative array parameters may be unset
     by using subscript syntax on NAME, which should be quoted (or the
     entire command prefixed with noglob) to protect the subscript from
     filename generation.

     If the -m flag is specified the arguments are taken as patterns
     (should be quoted) and all parameters with matching names are
     unset.  Note that this cannot be used when unsetting associative
     array elements, as the subscript will be treated as part of the
     pattern.

     The -v flag specifies that NAME refers to parameters. This is the
     default behaviour.

     unset -f is equivalent to unfunction.

unsetopt [ {+|-}OPTIONS | {+|-}o OPTION_NAME ] [ NAME ... ]
     Unset the options for the shell.  All options specified either
     with flags or by name are unset.  If no arguments are supplied,
     the names of all options currently unset are printed.  If the -m
     flag is given the arguments are taken as patterns (which should be
     quoted to preserve them from being interpreted as glob patterns),
     and all options with names matching these patterns are unset.

vared
     See *note Zle Builtins::.

wait [ JOB ... ]
     Wait for the specified jobs or processes.  If JOB is not given
     then all currently active child processes are waited for.  Each
     JOB can be either a job specification or the process ID of a job
     in the job table.  The exit status from this command is that of
     the job waited for.

whence [ -vcwfpams ] NAME ...
     For each name, indicate how it would be interpreted if used as a
     command name.


    -v
          Produce a more verbose report.

    -c
          Print the results in a `csh'-like format.  This takes
          precedence over -v.

    -w
          For each NAME, print `NAME: WORD' where WORD is one of alias,
          builtin, command, function, hashed, reserved or none,
          according as NAME corresponds to an alias, a built-in
          command, an external command, a shell function, a command
          defined with the hash builtin, a reserved word, or is not
          recognised.  This takes precedence over -v and -c.

    -f
          Causes the contents of a shell function to be displayed,
          which would otherwise not happen unless the -c flag were used.

    -p
          Do a path search for NAME even if it is an alias, reserved
          word, shell function or builtin.

    -a
          Do a search for all occurrences of NAME throughout the
          command path.  Normally only the first occurrence is printed.

    -m
          The arguments are taken as patterns (should be quoted), and
          the information is displayed for each command matching one of
          these patterns.

    -s
          If a pathname contains symlinks, print the symlink-free
          pathname as well.


where [ -wpms ] NAME ...
     Equivalent to whence -ca.

which [ -wpams ] NAME ...
     Equivalent to whence -c.

zcompile [ -U ] [ -z | -k ] [ -R | -M ] FILE [ NAME ... ]
zcompile -ca [ -m ] [ -R | -M ] FILE [ NAME ... ]
zcompile -t FILE [ NAME ... ]
     This builtin command can be used to compile functions or scripts,
     storing the compiled form in a file, and to examine files
     containing the compiled form.  This allows faster autoloading of
     functions and execution of scripts by avoiding parsing of the text
     when the files are read.

     The first form (without the -c, -a or -t options) creates a
     compiled file.  If only the FILE argument is given, the output
     file has the name `FILE.zwc' and will be placed in the same
     directory as the FILE.  The shell will load the compiled file
     instead of the normal function file when the function is
     autoloaded; see *note Functions:: for a description of how
     autoloaded functions are searched.  The extension .zwc stands for
     `zsh word code'.

     If there is at least one NAME argument, all the named files are
     compiled into the output FILE given as the first argument.  If
     FILE does not end in .zwc, this extension is automatically
     appended.  Files containing multiple compiled functions are called
     `digest' files, and are intended to be used as elements of the
     FPATH/fpath special array.

     The second form, with the -c or -a options, writes the compiled
     definitions for all the named functions into FILE.  For -c, the
     names must be functions currently defined in the shell, not those
     marked for autoloading.  Undefined functions that are marked for
     autoloading may be written by using the -a option, in which case
     the fpath is searched and the contents of the definition files for
     those functions, if found, are compiled into FILE.  If both -c and
     -a are given, names of both defined functions and functions marked
     for autoloading may be given.  In either case, the functions in
     files written with the -c or -a option will be autoloaded as if the
     KSH_AUTOLOAD option were unset.

     The reason for handling loaded and not-yet-loaded functions with
     different options is that some definition files for autoloading
     define multiple functions, including the function with the same
     name as the file, and, at the end, call that function.  In such
     cases the output of `zcompile -c' does not include the additional
     functions defined in the file, and any other initialization code
     in the file is lost.  Using `zcompile -a' captures all this extra
     information.

     If the -m option is combined with -c or -a, the NAMEs are used as
     patterns and all functions whose names match one of these patterns
     will be written. If no NAME is given, the definitions of all
     functions currently defined or marked as autoloaded will be
     written.

     The third form, with the -t option, examines an existing compiled
     file.  Without further arguments, the names of the original files
     compiled into it are listed.  The first line of output shows the
     version of the shell which compiled the file and how the file will
     be used (i.e. by reading it directly or by mapping it into memory).
     With arguments, nothing is output and the return status is set to
     zero if definitions for _all_ NAMEs were found in the compiled
     file, and non-zero if the definition for at least one NAME was not
     found.

     Other options:


    -U
          Aliases are not expanded when compiling the NAMEd files.

    -R
          When the compiled file is read, its contents are copied into
          the shell's memory, rather than memory-mapped (see -M).  This
          happens automatically on systems that do not support memory
          mapping.

          When compiling scripts instead of autoloadable functions, it
          is often desirable to use this option; otherwise the whole
          file, including the code to define functions which have
          already been defined, will remain mapped, consequently
          wasting memory.

    -M
          The compiled file is mapped into the shell's memory when
          read. This is done in such a way that multiple instances of
          the shell running on the same host will share this mapped
          file.  If neither -R nor -M is given, the zcompile builtin
          decides what to do based on the size of the compiled file.

    -k
    -z
          These options are used when the compiled file contains
          functions which are to be autoloaded. If -z is given, the
          function will be autoloaded as if the KSH_AUTOLOAD option is
          _not_ set, even if it is set at the time the compiled file is
          read, while if the -k is given, the function will be loaded
          as if KSH_AUTOLOAD _is_ set.  These options also take
          precedence over any -k or -z options specified to the
          autoload builtin. If neither of these options is given, the
          function will be loaded as determined by the setting of the
          KSH_AUTOLOAD option at the time the compiled file is read.

          These options may also appear as many times as necessary
          between the listed NAMEs to specify the loading style of all
          following functions, up to the next -k or -z.


     The created file always contains two versions of the compiled
     format, one for big-endian machines and one for small-endian
     machines.  The upshot of this is that the compiled file is machine
     independent and if it is read or mapped, only one half of the file
     is actually used (and mapped).

zformat
     See *note The zsh/zutil Module::.

zftp
     See *note The zsh/zftp Module::.

zle
     See *note Zle Builtins::.

zmodload [ -dL ] [ ... ]
zmodload -F [ -lLme -P param ] MODULE [+-]FEATURE...
zmodload -e [ -A ] [ ... ]
zmodload [ -a [ -bcpf [ -I ] ] ] [ -iL ] ...
zmodload -u [ -abcdpf [ -I ] ] [ -iL ] ...
zmodload -A [ -L ] [ MODALIAS[=MODULE] ... ]
zmodload -R MODALIAS ...
     Performs operations relating to zsh's loadable modules.  Loading
     of modules while the shell is running (`dynamical loading') is not
     available on all operating systems, or on all installations on a
     particular operating system, although the zmodload command itself
     is always available and can be used to manipulate modules built
     into versions of the shell executable without dynamical loading.

     Without arguments the names of all currently loaded binary modules
     are printed.  The -L option causes this list to be in the form of a
     series of zmodload commands.  Forms with arguments are:


    zmodload [ -i ] NAME ...
    zmodload -u [ -i ] NAME ...
          In the simplest case, zmodload loads a binary module.  The
          module must be in a file with a name consisting of the
          specified NAME followed by a standard suffix, usually `.so'
          (`.sl' on HPUX).  If the module to be loaded is already
          loaded the duplicate module is ignored.  If zmodload detects
          an inconsistency, such as an invalid module name or circular
          dependency list, the current code block is aborted.   Hence
          `zmodload MODULE 2>/dev/null' is sufficient to test whether a
          module is available.  If it is available, the module is
          loaded if necessary, while if it is not available, non-zero
          status is silently returned.  The option -i is accepted for
          compatibility but has no effect.

          The NAMEd module is searched for in the same way a command
          is, using $module_path instead of $path.  However, the path
          search is performed even when the module name contains a `/',
          which it usually does.  There is no way to prevent the path
          search.

          If the module supports features (see below), zmodload tries to
          enable all features when loading a module.  If the module was
          successfully loaded but not all features could be enabled,
          zmodload returns status 2.

          With -u, zmodload unloads modules.  The same NAME must be
          given that was given when the module was loaded, but it is not
          necessary for the module to exist in the file system.  The -i
          option suppresses the error if the module is already unloaded
          (or was never loaded).

          Each module has a boot and a cleanup function.  The module
          will not be loaded if its boot function fails.  Similarly a
          module can only be unloaded if its cleanup function runs
          successfully.

    zmodload -F [ -almLe -P param ] MODULE [+-]FEATURE...
          zmodload -F allows more selective control over the features
          provided by modules.  With no options apart from -F, the
          module named MODULE is loaded, if it was not already loaded,
          and the list of FEATUREs is set to the required state.  If no
          FEATUREs are specified, the module is loaded, if it was not
          already loaded, but the state of features is unchanged.  Each
          feature may be preceded by a + to turn the feature on, or -
          to turn it off; the + is assumed if neither character is
          present.  Any feature not explicitly mentioned is left in its
          current state; if the module was not previously loaded this
          means any such features will remain disabled.  The return
          status is zero if all features were set, 1 if the module
          failed to load, and 2 if some features could not be set (for
          example, a parameter couldn't be added because there was a
          different parameter of the same name) but the module was
          loaded.

          The standard features are builtins, conditions, parameters
          and math functions; these are indicated by the prefix `b:',
          `c:' (`C:' for an infix condition), `p:' and `f:',
          respectively, followed by the name that the corresponding
          feature would have in the shell.  For example, `b:strftime'
          indicates a builtin named strftime and p:EPOCHSECONDS
          indicates a parameter named EPOCHSECONDS.  The module may
          provide other (`abstract') features of its own as indicated
          by its documentation; these have no prefix.

          With -l or -L, features provided by the module are listed.
          With -l alone, a list of features together with their states
          is shown, one feature per line.  With -L alone, a zmodload -F
          command that would cause enabled features of the module to be
          turned on is shown.  With -lL, a zmodload -F command that
          would cause all the features to be set to their current state
          is shown.  If one of these combinations is given the option
          -P PARAM then the parameter param is set to an array of
          features, either features together with their state or (if -L
          alone is given) enabled features.

          With the option -L the module name may be omitted; then a list
          of all enabled features for all modules providing features is
          printed in the form of zmodload -F commands.  If -l is also
          given, the state of both enabled and disabled features is
          output in that form.

          A set of features may be provided together with -l or -L and a
          module name; in that case only the state of those features is
          considered.  Each feature may be preceded by + or - but the
          character has no effect.  If no set of features is provided,
          all features are considered.

          With -e, the command first tests that the module is loaded;
          if it is not, status 1 is returned.  If the module is loaded,
          the list of features given as an argument is examined.  Any
          feature given with no prefix is simply tested to see if the
          module provides it; any feature given with a prefix + or - is
          tested to see if is provided and in the given state.  If the
          tests on all features in the list succeed, status 0 is
          returned, else status 1.

          With -m, each entry in the given list of features is taken as
          a pattern to be matched against the list of features provided
          by the module.  An initial + or - must be given explicitly.
          This may not be combined with the -a option as autoloads must
          be specified explicitly.

          With -a, the given list of features is marked for autoload
          from the specified module, which may not yet be loaded.  An
          optional + may appear before the feature name.  If the
          feature is prefixed with -, any existing autoload is removed.
          The options -l and -L may be used to list autoloads.
          Autoloading is specific to individual features; when the
          module is loaded only the requested feature is enabled.
          Autoload requests are preserved if the module is subsequently
          unloaded until an explicit `zmodload -Fa MODULE -FEATURE' is
          issued.  It is not an error to request an autoload for a
          feature of a module that is already loaded.

          When the module is loaded each autoload is checked against
          the features actually provided by the module; if the feature
          is not provided the autoload request is deleted.  A warning
          message is output; if the module is being loaded to provide a
          different feature, and that autoload is successful, there is
          no effect on the status of the current command.  If the
          module is already loaded at the time when zmodload -Fa is
          run, an error message is printed and status 1 returned.

          zmodload -Fa can be used with the -l, -L, -e and -P options
          for listing and testing the existence of autoloadable
          features.  In this case -l is ignored if -L is specified.
          zmodload -FaL with no module name lists autoloads for all
          modules.

          Note that only standard features as described above can be
          autoloaded; other features require the module to be loaded
          before enabling.

    zmodload -d [ -L ] [ NAME ]
    zmodload -d NAME DEP ...
    zmodload -ud NAME [ DEP ... ]
          The -d option can be used to specify module dependencies.
          The modules named in the second and subsequent arguments will
          be loaded before the module named in the first argument.

          With -d and one argument, all dependencies for that module
          are listed.  With -d and no arguments, all module
          dependencies are listed.  This listing is by default in a
          Makefile-like format.  The -L option changes this format to a
          list of zmodload -d commands.

          If -d and -u are both used, dependencies are removed.  If
          only one argument is given, all dependencies for that module
          are removed.

    zmodload -ab [ -L ]
    zmodload -ab [ -i ] NAME [ BUILTIN ... ]
    zmodload -ub [ -i ] BUILTIN ...
          The -ab option defines autoloaded builtins.  It defines the
          specified BUILTINs.  When any of those builtins is called,
          the module specified in the first argument is loaded and all
          its features are enabled (for selective control of features
          use `zmodload -F -a' as described above).  If only the NAME
          is given, one builtin is defined, with the same name as the
          module.  -i suppresses the error if the builtin is already
          defined or autoloaded, but not if another builtin of the same
          name is already defined.

          With -ab and no arguments, all autoloaded builtins are
          listed, with the module name (if different) shown in
          parentheses after the builtin name.  The -L option changes
          this format to a list of zmodload -a commands.

          If -b is used together with the -u option, it removes builtins
          previously defined with -ab.  This is only possible if the
          builtin is not yet loaded.  -i suppresses the error if the
          builtin is already removed (or never existed).

          Autoload requests are retained if the module is subsequently
          unloaded until an explicit `zmodload -ub BUILTIN' is issued.

    zmodload -ac [ -IL ]
    zmodload -ac [ -iI ] NAME [ COND ... ]
    zmodload -uc [ -iI ] COND ...
          The -ac option is used to define autoloaded condition codes.
          The COND strings give the names of the conditions defined by
          the module. The optional -I option is used to define infix
          condition names. Without this option prefix condition names
          are defined.

          If given no condition names, all defined names are listed (as
          a series of zmodload commands if the -L option is given).

          The -uc option removes definitions for autoloaded conditions.

    zmodload -ap [ -L ]
    zmodload -ap [ -i ] NAME [ PARAMETER ... ]
    zmodload -up [ -i ] PARAMETER ...
          The -p option is like the -b and -c options, but makes
          zmodload work on autoloaded parameters instead.

    zmodload -af [ -L ]
    zmodload -af [ -i ] NAME [ FUNCTION ... ]
    zmodload -uf [ -i ] FUNCTION ...
          The -f option is like the -b, -p, and -c options, but makes
          zmodload work on autoloaded math functions instead.

    zmodload -a [ -L ]
    zmodload -a [ -i ] NAME [ BUILTIN ... ]
    zmodload -ua [ -i ] BUILTIN ...
          Equivalent to -ab and -ub.

    zmodload -e [ -A ] [ STRING ... ]
          The -e option without arguments lists all loaded modules; if
          the -A option is also given, module aliases corresponding to
          loaded modules are also shown.  If arguments are provided,
          nothing is printed; the return status is set to zero if all
          STRINGs given as arguments are names of loaded modules and to
          one if at least on STRING is not the name of a loaded module.
          This can be used to test for the availability of things
          implemented by modules.  In this case, any aliases are
          automatically resolved and the -A flag is not used.

    zmodload -A [ -L ] [ MODALIAS[=MODULE] ... ]
          For each argument, if both MODALIAS and MODULE are given,
          define MODALIAS to be an alias for the module MODULE.  If the
          module MODALIAS is ever subsequently requested, either via a
          call to zmodload or implicitly, the shell will attempt to load
          MODULE instead.  If MODULE is not given, show the definition
          of MODALIAS.  If no arguments are given, list all defined
          module aliases.  When listing, if the -L flag was also given,
          list the definition as a zmodload command to recreate the
          alias.

          The existence of aliases for modules is completely
          independent of whether the name resolved is actually loaded
          as a module: while the alias exists, loading and unloading
          the module under any alias has exactly the same effect as
          using the resolved name, and does not affect the connection
          between the alias and the resolved name which can be removed
          either by zmodload -R or by redefining the alias.  Chains of
          aliases (i.e. where the first resolved name is itself an
          alias) are valid so long as these are not circular.  As the
          aliases take the same format as module names, they may
          include path separators:  in this case, there is no
          requirement for any part of the path named to exist as the
          alias will be resolved first.  For example, `any/old/alias'
          is always a valid alias.

          Dependencies added to aliased modules are actually added to
          the resolved module; these remain if the alias is removed.
          It is valid to create an alias whose name is one of the
          standard shell modules and which resolves to a different
          module.  However, if a module has dependencies, it will not
          be possible to use the module name as an alias as the module
          will already be marked as a loadable module in its own right.

          Apart from the above, aliases can be used in the zmodload
          command anywhere module names are required.  However, aliases
          will not be shown in lists of loaded modules with a bare
          `zmodload'.

    zmodload -R MODALIAS ...
          For each MODALIAS argument that was previously defined as a
          module alias via zmodload -A, delete the alias.  If any was
          not defined, an error is caused and the remainder of the line
          is ignored.


     Note that zsh makes no distinction between modules that were linked
     into the shell and modules that are loaded dynamically. In both
     cases this builtin command has to be used to make available the
     builtins and other things defined by modules (unless the module is
     autoloaded on these definitions). This is true even for systems
     that don't support dynamic loading of modules.

zparseopts
     See *note The zsh/zutil Module::.

zprof
     See *note The zsh/zprof Module::.

zpty
     See *note The zsh/zpty Module::.

zregexparse
     See *note The zsh/zutil Module::.

zsocket
     See *note The zsh/net/socket Module::.

zstyle
     See *note The zsh/zutil Module::.

ztcp
     See *note The zsh/net/tcp Module::.


File: zsh.info,  Node: Zsh Line Editor,  Next: Completion Widgets,  Prev: Shell Builtin Commands,  Up: Top

18 Zsh Line Editor
******************



18.1 Description
================

If the ZLE option is set (which it is by default in interactive shells)
and the shell input is attached to the terminal, the user is able to
edit command lines.

There are two display modes.  The first, multiline mode, is the
default.  It only works if the TERM parameter is set to a valid
terminal type that can move the cursor up.  The second, single line
mode, is used if TERM is invalid or incapable of moving the cursor up,
or if the SINGLE_LINE_ZLE option is set.  This mode is similar to
`ksh', and uses no termcap sequences.  If TERM is "emacs", the ZLE
option will be unset by default.

The parameters BAUD, COLUMNS, and LINES are also used by the line
editor.  *note Parameters Used By The Shell::.

The parameter zle_highlight is also used by the line editor; *note
Character Highlighting::.  Highlighting of special characters and the
region between the cursor and the mark (as set with set-mark-command in
Emacs mode) is enabled by default; consult this reference for more
information.  Irascible conservatives will wish to know that all
highlighting may be disabled by the following setting:


     zle_highlight=(none)


* Menu:

* Keymaps::
* Zle Builtins::
* Zle Widgets::
* Character Highlighting::


File: zsh.info,  Node: Keymaps,  Next: Zle Builtins,  Up: Zsh Line Editor

18.2 Keymaps
============

A keymap in ZLE contains a set of bindings between key sequences and
ZLE commands.  The empty key sequence cannot be bound.

There can be any number of keymaps at any time, and each keymap has one
or more names.  If all of a keymap's names are deleted, it disappears.  bindkey
can be used to manipulate keymap names.

Initially, there are six keymaps:


emacs
     EMACS emulation

viins
     vi emulation - insert mode

vicmd
     vi emulation - command mode

isearch
     incremental search mode

command
     read a command name

.safe
     fallback keymap

The `.safe' keymap is special.  It can never be altered, and the name
can never be removed.  However, it can be linked to other names, which
can be removed.  In the future other special keymaps may be added;
users should avoid using names beginning with `.' for their own keymaps.

In addition to these names, either `emacs' or `viins' is also linked to
the name `main'.  If one of the VISUAL or EDITOR environment variables
contain the string `vi' when the shell starts up then it will be
`viins', otherwise it will be `emacs'.  bindkey's -e and -v options
provide a convenient way to override this default choice.

When the editor starts up, it will select the `main' keymap.  If that
keymap doesn't exist, it will use `.safe' instead.

In the `.safe' keymap, each single key is bound to self-insert, except
for ^J (line feed) and ^M (return) which are bound to accept-line.
This is deliberately not pleasant to use; if you are using it, it means
you deleted the main keymap, and you should put it back.

18.2.1 Reading Commands
-----------------------

When ZLE is reading a command from the terminal, it may read a sequence
that is bound to some command and is also a prefix of a longer bound
string.  In this case ZLE will wait a certain time to see if more
characters are typed, and if not (or they don't match any longer
string) it will execute the binding.  This timeout is defined by the
KEYTIMEOUT parameter; its default is 0.4 sec.  There is no timeout if
the prefix string is not itself bound to a command.

The key timeout is also applied when ZLE is reading the bytes from a
multibyte character string when it is in the appropriate mode.  (This
requires that the shell was compiled with multibyte mode enabled;
typically also the locale has characters with the UTF-8 encoding,
although any multibyte encoding known to the operating system is
supported.)  If the second or a subsequent byte is not read within the
timeout period, the shell acts as if ? were typed and resets the input
state.

As well as ZLE commands, key sequences can be bound to other strings,
by using `bindkey -s'.  When such a sequence is read, the replacement
string is pushed back as input, and the command reading process starts
again using these fake keystrokes.  This input can itself invoke
further replacement strings, but in order to detect loops the process
will be stopped if there are twenty such replacements without a real
command being read.

A key sequence typed by the user can be turned into a command name for
use in user-defined widgets with the read-command widget, described in
*note Miscellaneous:: below.



File: zsh.info,  Node: Zle Builtins,  Next: Zle Widgets,  Prev: Keymaps,  Up: Zsh Line Editor

18.3 Zle Builtins
=================

The ZLE module contains three related builtin commands. The bindkey
command manipulates keymaps and key bindings; the vared command invokes
ZLE on the value of a shell parameter; and the zle command manipulates
editing widgets and allows command line access to ZLE commands from
within shell functions.


bindkey [ OPTIONS ] -l [ -L ] [ KEYMAP ... ]
bindkey [ OPTIONS ] -d
bindkey [ OPTIONS ] -D KEYMAP ...
bindkey [ OPTIONS ] -A OLD-KEYMAP NEW-KEYMAP
bindkey [ OPTIONS ] -N NEW-KEYMAP [ OLD-KEYMAP ]
bindkey [ OPTIONS ] -m
bindkey [ OPTIONS ] -r IN-STRING ...
bindkey [ OPTIONS ] -s IN-STRING OUT-STRING ...
bindkey [ OPTIONS ] IN-STRING COMMAND ...
bindkey [ OPTIONS ] [ IN-STRING ]
     bindkey's options can be divided into three categories: keymap
     selection for the current command, operation selection, and
     others.  The keymap selection options are:


    -e
          Selects keymap `emacs' for any operations by the current
          command, and also links `emacs' to `main' so that it is
          selected by default the next time the editor starts.

    -v
          Selects keymap `viins' for any operations by the current
          command, and also links `viins' to `main' so that it is
          selected by default the next time the editor starts.

    -a
          Selects keymap `vicmd' for any operations by the current
          command.

    -M KEYMAP
          The KEYMAP specifies a keymap name that is selected for any
          operations by the current command.


     If a keymap selection is required and none of the options above
     are used, the `main' keymap is used.  Some operations do not
     permit a keymap to be selected, namely:


    -l
          List all existing keymap names; if any arguments are given,
          list just those keymaps.

          If the -L option is also used, list in the form of bindkey
          commands to create or link the keymaps.  `bindkey -lL main'
          shows which keymap is linked to `main', if any, and hence if
          the standard emacs or vi emulation is in effect.  This option
          does not show the .safe keymap because it cannot be created
          in that fashion; however, neither is `bindkey -lL .safe'
          reported as an error, it simply outputs nothing.

    -d
          Delete all existing keymaps and reset to the default state.

    -D KEYMAP ...
          Delete the named KEYMAPs.

    -A OLD-KEYMAP NEW-KEYMAP
          Make the NEW-KEYMAP name an alias for OLD-KEYMAP, so that
          both names refer to the same keymap.  The names have equal
          standing; if either is deleted, the other remains.  If there
          is already a keymap with the NEW-KEYMAP name, it is deleted.

    -N NEW-KEYMAP [ OLD-KEYMAP ]
          Create a new keymap, named NEW-KEYMAP.  If a keymap already
          has that name, it is deleted.  If an OLD-KEYMAP name is
          given, the new keymap is initialized to be a duplicate of it,
          otherwise the new keymap will be empty.


     To use a newly created keymap, it should be linked to main.  Hence
     the sequence of commands to create and use a new keymap `mymap'
     initialized from the emacs keymap (which remains unchanged) is:


          bindkey -N mymap emacs
          bindkey -A mymap main

     Note that while `bindkey -A NEWMAP main' will work when NEWMAP is
     emacs or viins, it will not work for vicmd, as switching from vi
     insert to command mode becomes impossible.

     The following operations act on the `main' keymap if no keymap
     selection option was given:


    -m
          Add the built-in set of meta-key bindings to the selected
          keymap.  Only keys that are unbound or bound to self-insert
          are affected.

    -r IN-STRING ...
          Unbind the specified IN-STRINGs in the selected keymap.  This
          is exactly equivalent to binding the strings to undefined-key.

          When -R is also used, interpret the IN-STRINGs as ranges.

          When -p is also used, the IN-STRINGs specify prefixes.  Any
          binding that has the given IN-STRING as a prefix, not
          including the binding for the IN-STRING itself, if any, will
          be removed.  For example,


               bindkey -rpM viins '^['

          will remove all bindings in the vi-insert keymap beginning
          with an escape character (probably cursor keys), but leave
          the binding for the escape character itself (probably
          vi-cmd-mode).  This is incompatible with the option -R.

    -s IN-STRING OUT-STRING ...
          Bind each IN-STRING to each OUT-STRING.  When IN-STRING is
          typed, OUT-STRING will be pushed back and treated as input to
          the line editor.  When -R is also used, interpret the
          IN-STRINGs as ranges.

    IN-STRING COMMAND ...
          Bind each IN-STRING to each COMMAND.  When -R is used,
          interpret the IN-STRINGs as ranges.

    [ IN-STRING ]
          List key bindings.  If an IN-STRING is specified, the binding
          of that string in the selected keymap is displayed.
          Otherwise, all key bindings in the selected keymap are
          displayed.  (As a special case, if the -e or -v option is
          used alone, the keymap is _not_ displayed - the implicit
          linking of keymaps is the only thing that happens.)

          When the option -p is used, the IN-STRING must be present.
          The listing shows all bindings which have the given key
          sequence as a prefix, not including any bindings for the key
          sequence itself.

          When the -L option is used, the list is in the form of bindkey
          commands to create the key bindings.


     When the -R option is used as noted above, a valid range consists
     of two characters, with an optional `-' between them.  All
     characters between the two specified, inclusive, are bound as
     specified.

     For either IN-STRING or OUT-STRING, the following escape sequences
     are recognised:


    \a
          bell character

    \b
          backspace

    \e, \E
          escape

    \f
          form feed

    \n
          linefeed (newline)

    \r
          carriage return

    \t
          horizontal tab

    \v
          vertical tab

    \NNN
          character code in octal

    \xNN
          character code in hexadecimal

    \M[-]X
          character with meta bit set

    \C[-]X
          control character

    ^X
          control character

     In all other cases, `\' escapes the following character.  Delete is
     written as `^?'.  Note that `\M^?' and `^\M?' are not the same,
     and that (unlike emacs), the bindings `\M-X' and `\eX' are
     entirely distinct, although they are initialized to the same
     bindings by `bindkey -m'.

vared [ -Aache ] [ -p PROMPT ] [ -r RPROMPT ]
[ -M MAIN-KEYMAP ] [ -m VICMD-KEYMAP ]
[ -t TTY ] NAME
     The value of the parameter NAME is loaded into the edit buffer,
     and the line editor is invoked.  When the editor exits, NAME is
     set to the string value returned by the editor.  When the -c flag
     is given, the parameter is created if it doesn't already exist.
     The -a flag may be given with -c to create an array parameter, or
     the -A flag to create an associative array.  If the type of an
     existing parameter does not match the type to be created, the
     parameter is unset and recreated.

     If an array or array slice is being edited, separator characters
     as defined in $IFS will be shown quoted with a backslash, as will
     backslashes themselves.  Conversely, when the edited text is split
     into an array, a backslash quotes an immediately following
     separator character or backslash; no other special handling of
     backslashes, or any handling of quotes, is performed.

     Individual elements of existing array or associative array
     parameters may be edited by using subscript syntax on NAME.  New
     elements are created automatically, even without -c.

     If the -p flag is given, the following string will be taken as the
     prompt to display at the left.  If the -r flag is given, the
     following string gives the prompt to display at the right.  If the
     -h flag is specified, the history can be accessed from ZLE. If the
     -e flag is given, typing ^D (Control-D) on an empty line causes
     vared to exit immediately with a non-zero return value.

     The -M option gives a keymap to link to the main keymap during
     editing, and the -m option gives a keymap to link to the vicmd
     keymap during editing.  For vi-style editing, this allows a pair
     of keymaps to override viins and vicmd.  For emacs-style editing,
     only -M is normally needed but the -m option may still be used.
     On exit, the previous keymaps will be restored.

     If `-t TTY' is given, TTY is the name of a terminal device to be
     used instead of the default /dev/tty.  If TTY does not refer to a
     terminal an error is reported.

zle
zle -l [ -L | -a ] [ STRING ... ]
zle -D WIDGET ...
zle -A OLD-WIDGET NEW-WIDGET
zle -N WIDGET [ FUNCTION ]
zle -C WIDGET COMPLETION-WIDGET FUNCTION
zle -R [ -c ] [ DISPLAY-STRING ] [ STRING ... ]
zle -M STRING
zle -U STRING
zle -K KEYMAP
zle -F [ -L ] [ FD [ HANDLER ] ]
zle -I
zle WIDGET [ -n NUM ] [ -Nw ] [ -K KEYMAP ] ARGS ...
     The zle builtin performs a number of different actions concerning
     ZLE.

     With no options and no arguments, only the return status will be
     set.  It is zero if ZLE is currently active and widgets could be
     invoked using this builtin command and non-zero otherwise.  Note
     that even if non-zero status is returned, zle may still be active
     as part of the completion system; this does not allow direct calls
     to ZLE widgets.

     Otherwise, which operation it performs depends on its options:


    -l [ -L | -a ]
          List all existing user-defined widgets.  If the -L option is
          used, list in the form of zle commands to create the widgets.

          When combined with the -a option, all widget names are listed,
          including the builtin ones. In this case the -L option is
          ignored.

          If at least one STRING is given, nothing will be printed but
          the return status will be zero if all STRINGs are names of
          existing widgets (or of user-defined widgets if the -a flag
          is not given) and non-zero if at least one STRING is not a
          name of an defined widget.

    -D WIDGET ...
          Delete the named WIDGETs.

    -A OLD-WIDGET NEW-WIDGET
          Make the NEW-WIDGET name an alias for OLD-WIDGET, so that
          both names refer to the same widget.  The names have equal
          standing; if either is deleted, the other remains.  If there
          is already a widget with the NEW-WIDGET name, it is deleted.

    -N WIDGET [ FUNCTION ]
          Create a user-defined widget.  If there is already a widget
          with the specified name, it is overwritten.  When the new
          widget is invoked from within the editor, the specified shell
          FUNCTION is called.  If no function name is specified, it
          defaults to the same name as the widget.  For further
          information, see the section _Widgets_ in *note Zsh Line
          Editor::.

    -C WIDGET COMPLETION-WIDGET FUNCTION
          Create a user-defined completion widget named WIDGET. The
          completion widget will behave like the built-in
          completion-widget whose name is given as COMPLETION-WIDGET.
          To generate the completions, the shell function FUNCTION will
          be called.  For further information, see *note Completion
          Widgets::.

    -R [ -c ] [ DISPLAY-STRING ] [ STRING ... ]
          Redisplay the command line; this is to be called from within
          a user-defined widget to allow changes to become visible.  If
          a DISPLAY-STRING is given and not empty, this is shown in the
          status line (immediately below the line being edited).

          If the optional STRINGs are given they are listed below the
          prompt in the same way as completion lists are printed. If no
          STRINGs are given but the -c option is used such a list is
          cleared.

          Note that this option is only useful for widgets that do not
          exit immediately after using it because the strings displayed
          will be erased immediately after return from the widget.

          This command can safely be called outside user defined
          widgets; if zle is active, the display will be refreshed,
          while if zle is not active, the command has no effect.  In
          this case there will usually be no other arguments.

          The status is zero if zle was active, else one.

    -M STRING
          As with the -R option, the STRING will be displayed below the
          command line; unlike the -R option, the string will not be
          put into the status line but will instead be printed normally
          below the prompt.  This means that the STRING will still be
          displayed after the widget returns (until it is overwritten
          by subsequent commands).

    -U STRING
          This pushes the characters in the STRING onto the input stack
          of ZLE.  After the widget currently executed finishes ZLE
          will behave as if the characters in the STRING were typed by
          the user.

          As ZLE uses a stack, if this option is used repeatedly the
          last string pushed onto the stack will be processed first.
          However, the characters in each STRING will be processed in
          the order in which they appear in the string.

    -K KEYMAP
          Selects the keymap named KEYMAP.  An error message will be
          displayed if there is no such keymap.

          This keymap selection affects the interpretation of following
          keystrokes within this invocation of ZLE.  Any following
          invocation (e.g., the next command line) will start as usual
          with the `main' keymap selected.

    -F [ -L ] [ FD [ HANDLER ] ]
          Only available if your system supports one of the `poll' or
          `select' system calls; most modern systems do.

          Installs HANDLER (the name of a shell function) to handle
          input from file descriptor FD.  When zle is attempting to
          read data, it will examine both the terminal and the list of
          handled FD's.  If data becomes available on a handled FD, zle
          will call HANDLER with the fd which is ready for reading as
          the only argument.  If the handler produces output to the
          terminal, it should call `zle -I' before doing so (see
          below).  The handler should not attempt to read from the
          terminal.  Note that zle makes no attempt to check whether
          this fd is actually readable when installing the handler.
          The user must make their own arrangements for handling the
          file descriptor when zle is not active.

          Any number of handlers for any number of readable file
          descriptors may be installed.  Installing a handler for an FD
          which is already handled causes the existing handler to be
          replaced.

          If no HANDLER is given, but an FD is present, any handler for
          that FD is removed.  If there is none, an error message is
          printed and status 1 is returned.

          If no arguments are given, or the -L option is supplied, a
          list of handlers is printed in a form which can be stored for
          later execution.

          An FD (but not a HANDLER) may optionally be given with the -L
          option; in this case, the function will list the handler if
          any, else silently return status 1.

          Note that this feature should be used with care.  Activity on
          one of the FD's which is not properly handled can cause the
          terminal to become unusable.

          Here is a simple example of using this feature.  A connection
          to a remote TCP port is created using the ztcp command; see
          *note The zsh/net/tcp Module::.  Then a handler is installed
          which simply prints out any data which arrives on this
          connection.  Note that `select' will indicate that the file
          descriptor needs handling if the remote side has closed the
          connection; we handle that by testing for a failed read.
               if ztcp pwspc 2811; then
                 tcpfd=$REPLY
                 handler() {
                   zle -I
                   local line
                   if ! read -r line <&$1; then
                     # select marks this fd if we reach EOF,
                     # so handle this specially.
                     print "[Read on fd $1 failed, removing.]" >&2
                     zle -F $1
                     return 1
                   fi
                   print -r - $line
                 }
                 zle -F $tcpfd handler
               fi

    -I
          Unusually, this option is most useful outside ordinary widget
          functions, though it may be used within if normal output to
          the terminal is required.  It invalidates the current zle
          display in preparation for output; typically this will be
          from a trap function.  It has no effect if zle is not active.
          When a trap exits, the shell checks to see if the display
          needs restoring, hence the following will print output in
          such a way as not to disturb the line being edited:


               TRAPUSR1() {
                   # Invalidate zle display
                 [[ -o zle ]] && zle -I
                   # Show output
                 print Hello
               }

          In general, the trap function may need to test whether zle is
          active before using this method (as shown in the example),
          since the zsh/zle module may not even be loaded; if it is
          not, the command can be skipped.

          It is possible to call `zle -I' several times before control
          is returned to the editor; the display will only be
          invalidated the first time to minimise disruption.

          Note that there are normally better ways of manipulating the
          display from within zle widgets; see, for example, `zle -R'
          above.

          The returned status is zero if zle was invalidated, even
          though this may have been by a previous call to `zle -I' or
          by a system notification.  To test if a zle widget may be
          called at this point, execute zle with no arguments and
          examine the return status.

    WIDGET [ -n NUM ] [ -Nw ] [ -K KEYMAP ] ARGS ...
          Invoke the specified widget.  This can only be done when ZLE
          is active; normally this will be within a user-defined widget.

          With the options -n and -N, the current numerical argument
          will be saved and then restored after the call to widget; `-n
          NUM' sets the numerical argument temporarily to NUM, while
          `-N' sets it to the default, i.e. as if there were none.

          With the option -K, KEYMAP will be used as the current keymap
          during the execution of the widget.  The previous keymap will
          be restored when the widget exits.

          Normally, calling a widget in this way does not set the
          special parameter WIDGET and related parameters, so that the
          environment appears as if the top-level widget called by the
          user were still active.  With the option -w, WIDGET and
          related parameters are set to reflect the widget being
          executed by the zle call.

          Any further arguments will be passed to the widget; note that
          as standard argument handling is performed, any general
          argument list should be preceded by --.  If it is a shell
          function, these are passed down as positional parameters; for
          builtin widgets it is up to the widget in question what it
          does with them.  Currently arguments are only handled by the
          incremental-search commands, the history-search-forward and
          -backward and the corresponding functions prefixed by vi-,
          and by universal-argument.  No error is flagged if the
          command does not use the arguments, or only uses some of them.

          The return status reflects the success or failure of the
          operation carried out by the widget, or if it is a
          user-defined widget the return status of the shell function.

          A non-zero return status causes the shell to beep when the
          widget exits, unless the BEEP options was unset or the widget
          was called via the zle command.  Thus if a user defined
          widget requires an immediate beep, it should call the beep
          widget directly.




File: zsh.info,  Node: Zle Widgets,  Next: Character Highlighting,  Prev: Zle Builtins,  Up: Zsh Line Editor

18.4 Widgets
============

All actions in the editor are performed by `widgets'.  A widget's job is
simply to perform some small action.  The ZLE commands that key
sequences in keymaps are bound to are in fact widgets.  Widgets can be
user-defined or built in.

The standard widgets built into ZLE are listed in Standard Widgets
below.  Other built-in widgets can be defined by other modules (see
*note Zsh Modules::).  Each built-in widget has two names: its normal
canonical name, and the same name preceded by a `.'.  The `.' name is
special: it can't be rebound to a different widget.  This makes the
widget available even when its usual name has been redefined.

User-defined widgets are defined using `zle -N', and implemented as
shell functions.  When the widget is executed, the corresponding shell
function is executed, and can perform editing (or other) actions.  It
is recommended that user-defined widgets should not have names starting
with `.'.

18.5 User-Defined Widgets
=========================

User-defined widgets, being implemented as shell functions, can execute
any normal shell command.  They can also run other widgets (whether
built-in or user-defined) using the zle builtin command.  The standard
input of the function is closed to prevent external commands from
unintentionally blocking ZLE by reading from the terminal, but read -k
or read -q can be used to read characters.  Finally, they can examine
and edit the ZLE buffer being edited by reading and setting the special
parameters described below.

These special parameters are always available in widget functions, but
are not in any way special outside ZLE.  If they have some normal value
outside ZLE, that value is temporarily inaccessible, but will return
when the widget function exits.  These special parameters in fact have
local scope, like parameters created in a function using local.

Inside completion widgets and traps called while ZLE is active, these
parameters are available read-only.


BUFFER (scalar)
     The entire contents of the edit buffer.  If it is written to, the
     cursor remains at the same offset, unless that would put it
     outside the buffer.

BUFFERLINES (integer)
     The number of screen lines needed for the edit buffer currently
     displayed on screen (i.e. without any changes to the preceding
     parameters done after the last redisplay); read-only.

CONTEXT (scalar)
     The context in which zle was called to read a line; read-only.
     One of the values:
    start
          The start of a command line (at prompt PS1).

    cont
          A continuation to a command line (at prompt PS2).

    select
          In a select loop.

    vared
          Editing a variable in vared.


CURSOR (integer)
     The offset of the cursor, within the edit buffer.  This is in the
     range 0 to $#BUFFER, and is by definition equal to $#LBUFFER.
     Attempts to move the cursor outside the buffer will result in the
     cursor being moved to the appropriate end of the buffer.

CUTBUFFER (scalar)
     The last item cut using one of the `kill-' commands; the string
     which the next yank would insert in the line.  Later entries in
     the kill ring are in the array killring.  Note that the command
     `zle copy-region-as-kill STRING' can be used to set the text of
     the cut buffer from a shell function and cycle the kill ring in
     the same way as interactively killing text.

HISTNO (integer)
     The current history number.  Setting this has the same effect as
     moving up or down in the history to the corresponding history line.
     An attempt to set it is ignored if the line is not stored in the
     history.  Note this is not the same as the parameter HISTCMD,
     which always gives the number of the history line being added to
     the main shell's history.  HISTNO refers to the line being
     retrieved within zle.

KEYMAP (scalar)
     The name of the currently selected keymap; read-only.

KEYS (scalar)
     The keys typed to invoke this widget, as a literal string;
     read-only.

killring (array)
     The array of previously killed items, with the most recently
     killed first.  This gives the items that would be retrieved by a
     yank-pop in the same order.  Note, however, that the most recently
     killed item is in $CUTBUFFER; $killring shows the array of
     previous entries.

     The default size for the kill ring is eight, however the length
     may be changed by normal array operations.  Any empty string in
     the kill ring is ignored by the yank-pop command, hence the size
     of the array effectively sets the maximum length of the kill ring,
     while the number of non-zero strings gives the current length,
     both as seen by the user at the command line.

LASTABORTEDSEARCH (scalar)
     The last search string used by an interactive search that was
     aborted by the user (status 3 returned by the search widget).

LASTSEARCH (scalar)
     The last search string used by an interactive search; read-only.
     This is set even if the search failed (status 0, 1 or 2 returned
     by the search widget), but not if it was aborted by the user.

LASTWIDGET (scalar)
     The name of the last widget that was executed; read-only.

LBUFFER (scalar)
     The part of the buffer that lies to the left of the cursor
     position.  If it is assigned to, only that part of the buffer is
     replaced, and the cursor remains between the new $LBUFFER and the
     old $RBUFFER.

MARK (integer)
     Like CURSOR, but for the mark.

NUMERIC (integer)
     The numeric argument. If no numeric argument was given, this
     parameter is unset. When this is set inside a widget function,
     builtin widgets called with the zle builtin command will use the
     value assigned. If it is unset inside a widget function, builtin
     widgets called behave as if no numeric argument was given.

PENDING (integer)
     The number of bytes pending for input, i.e. the number of bytes
     which have already been typed and can immediately be read. On
     systems where the shell is not able to get this information, this
     parameter will always have a value of zero.  Read-only.

PREBUFFER (scalar)
     In a multi-line input at the secondary prompt, this read-only
     parameter contains the contents of the lines before the one the
     cursor is currently in.

PREDISPLAY (scalar)
     Text to be displayed before the start of the editable text buffer.
     This does not have to be a complete line; to display a complete
     line, a newline must be appended explicitly.  The text is reset on
     each new invocation (but not recursive invocation) of zle.

POSTDISPLAY (scalar)
     Text to be displayed after the end of the editable text buffer.
     This does not have to be a complete line; to display a complete
     line, a newline must be prepended explicitly.  The text is reset
     on each new invocation (but not recursive invocation) of zle.

RBUFFER (scalar)
     The part of the buffer that lies to the right of the cursor
     position.  If it is assigned to, only that part of the buffer is
     replaced, and the cursor remains between the old $LBUFFER and the
     new $RBUFFER.

REGION_ACTIVE (integer)
     Indicates if the region is currently active.  It can be assigned 0
     or 1 to deactivate and activate the region respectively; *note
     Character Highlighting::.

region_highlight (array)
     Each element of this array may be set to a string that describes
     highlighting for an arbitrary region of the command line that will
     take effect the next time the command line is redisplayed.
     Highlighting of the non-editable parts of the command line in
     PREDISPLAY and POSTDISPLAY are possible, but note that the P flag
     is needed for character indexing to include PREDISPLAY.

     Each string consists of the following parts:


    Optionally, a `P' to signify that the start and end offset that
          follow include any string set by the PREDISPLAY special
          parameter; this is needed if the predisplay string itself is
          to be highlighted.  Whitespace may follow the `P'.

    A start offset in the same units as CURSOR, terminated by
          whitespace.

    An end offset in the same units as CURSOR, terminated by
          whitespace.

    A highlight specification in the same format as
          used for contexts in the parameter zle_highlight, *note
          Character Highlighting::; for example, standout or
          fg=red,bold.



     For example,


          region_highlight=("P0 20 bold")

     specifies that the first twenty characters of the text including
     any predisplay string should be highlighted in bold.

     Note that the effect of region_highlight is not saved and
     disappears as soon as the line is accepted.  The line editor makes
     no attempt to keep the highlighting effect synchronised with the
     line as it is edited; hence region highlighting is best limited to
     static effects within user widgets.

WIDGET (scalar)
     The name of the widget currently being executed; read-only.

WIDGETFUNC (scalar)
     The name of the shell function that implements a widget defined
     with either zle -N or zle -C.  In the former case, this is the
     second argument to the zle -N command that defined the widget, or
     the first argument if there was no second argument.  In the latter
     case this is the the third argument to the zle -C command that
     defined the widget.  Read-only.

WIDGETSTYLE (scalar)
     Describes the implementation behind the completion widget
     currently being executed; the second argument that followed zle -C
     when the widget was defined.  This is the name of a builtin
     completion widget.  For widgets defined with zle -N this is set to
     the empty string.  Read-only.

ZLE_STATE (scalar)
     Contains a set of space-separated words that describe the current
     zle state.

     Currently, the only state shown is the insert mode as set by the
     overwrite-mode or vi-replace widgets.  The string contains
     `insert' if characters to be inserted on the command line move
     existing characters to the right, `overwrite' if characters to be
     inserted overwrite existing characters.



18.5.1 Special Widgets
----------------------

There are a few user-defined widgets which are special to the shell.
If they do not exist, no special action is taken.  The environment
provided is identical to that for any other editing widget.


zle-isearch-exit
     Executed at the end of incremental search at the point where the
     isearch prompt is removed from the display.  See
     zle-isearch-update for an example.

zle-isearch-update
     Executed within incremental search when the display is about to be
     redrawn.  Additional output below the incremental search prompt
     can be generated by using `zle -M' within the widget.  For example,


          zle-isearch-update() { zle -M "Line $HISTNO"; }
          zle -N zle-isearch-update

     Note the line output by `zle -M' is not deleted on exit from
     incremental search.  This can be done from a zle-isearch-exit
     widget:


          zle-isearch-exit() { zle -M ""; }
          zle -N zle-isearch-exit

zle-line-init
     Executed every time the line editor is started to read a new line
     of input.  The following example puts the line editor into vi
     command mode when it starts up.


          zle-line-init() { zle -K vicmd; }
          zle -N zle-line-init

     (The command inside the function sets the keymap directly; it is
     equivalent to zle vi-cmd-mode.)

zle-line-finish
     This is similar to zle-line-init but is executed every time the
     line editor has finished reading a line of input.

zle-keymap-select
     Executed every time the keymap changes, i.e. the special parameter
     KEYMAP is set to a different value, while the line editor is
     active.  Initialising the keymap when the line editor starts does
     not cause the widget to be called.

     The value $KEYMAP within the function reflects the new keymap.  The
     old keymap is passed as the sole argument.

     This can be used for detecting switches between the vi command
     (vicmd) and insert (usually main) keymaps.



18.6 Standard Widgets
=====================

The following is a list of all the standard widgets, and their default
bindings in emacs mode, vi command mode and vi insert mode (the
`emacs', `vicmd' and `viins' keymaps, respectively).

Note that cursor keys are bound to movement keys in all three keymaps;
the shell assumes that the cursor keys send the key sequences reported
by the terminal-handling library (termcap or terminfo).  The key
sequences shown in the list are those based on the VT100, common on
many modern terminals, but in fact these are not necessarily bound.  In
the case of the viins keymap, the initial escape character of the
sequences serves also to return to the vicmd keymap: whether this
happens is determined by the KEYTIMEOUT parameter, see *note
Parameters::.

* Menu:

* Movement::
* History Control::
* Modifying Text::
* Arguments::
* Completion::
* Miscellaneous::

File: zsh.info,  Node: Movement,  Next: History Control,  Up: Zle Widgets

18.6.1 Movement
---------------


vi-backward-blank-word (unbound) (B) (unbound)
     Move backward one word, where a word is defined as a series of
     non-blank characters.

backward-char (^B ESC-[D) (unbound) (unbound)
     Move backward one character.

vi-backward-char (unbound) (^H h ^?) (ESC-[D)
     Move backward one character, without changing lines.

backward-word (ESC-B ESC-b) (unbound) (unbound)
     Move to the beginning of the previous word.

emacs-backward-word
     Move to the beginning of the previous word.

vi-backward-word (unbound) (b) (unbound)
     Move to the beginning of the previous word, vi-style.

beginning-of-line (^A) (unbound) (unbound)
     Move to the beginning of the line.  If already at the beginning of
     the line, move to the beginning of the previous line, if any.

vi-beginning-of-line
     Move to the beginning of the line, without changing lines.

end-of-line (^E) (unbound) (unbound)
     Move to the end of the line.  If already at the end of the line,
     move to the end of the next line, if any.

vi-end-of-line (unbound) ($) (unbound)
     Move to the end of the line.  If an argument is given to this
     command, the cursor will be moved to the end of the line (argument
     - 1) lines down.

vi-forward-blank-word (unbound) (W) (unbound)
     Move forward one word, where a word is defined as a series of
     non-blank characters.

vi-forward-blank-word-end (unbound) (E) (unbound)
     Move to the end of the current word, or, if at the end of the
     current word, to the end of the next word, where a word is defined
     as a series of non-blank characters.

forward-char (^F ESC-[C) (unbound) (unbound)
     Move forward one character.

vi-forward-char (unbound) (space l) (ESC-[C)
     Move forward one character.

vi-find-next-char (^X^F) (f) (unbound)
     Read a character from the keyboard, and move to the next
     occurrence of it in the line.

vi-find-next-char-skip (unbound) (t) (unbound)
     Read a character from the keyboard, and move to the position just
     before the next occurrence of it in the line.

vi-find-prev-char (unbound) (F) (unbound)
     Read a character from the keyboard, and move to the previous
     occurrence of it in the line.

vi-find-prev-char-skip (unbound) (T) (unbound)
     Read a character from the keyboard, and move to the position just
     after the previous occurrence of it in the line.

vi-first-non-blank (unbound) (^) (unbound)
     Move to the first non-blank character in the line.

vi-forward-word (unbound) (w) (unbound)
     Move forward one word, vi-style.

forward-word (ESC-F ESC-f) (unbound) (unbound)
     Move to the beginning of the next word.  The editor's idea of a
     word is specified with the WORDCHARS parameter.

emacs-forward-word
     Move to the end of the next word.

vi-forward-word-end (unbound) (e) (unbound)
     Move to the end of the next word.

vi-goto-column (ESC-|) (|) (unbound)
     Move to the column specified by the numeric argument.

vi-goto-mark (unbound) (`) (unbound)
     Move to the specified mark.

vi-goto-mark-line (unbound) (') (unbound)
     Move to beginning of the line containing the specified mark.

vi-repeat-find (unbound) (;) (unbound)
     Repeat the last vi-find command.

vi-rev-repeat-find (unbound) (,) (unbound)
     Repeat the last vi-find command in the opposite direction.


File: zsh.info,  Node: History Control,  Next: Modifying Text,  Prev: Movement,  Up: Zle Widgets

18.6.2 History Control
----------------------


beginning-of-buffer-or-history (ESC-<) (unbound) (unbound)
     Move to the beginning of the buffer, or if already there, move to
     the first event in the history list.

beginning-of-line-hist
     Move to the beginning of the line.  If already at the beginning of
     the buffer, move to the previous history line.

beginning-of-history
     Move to the first event in the history list.

down-line-or-history (^N ESC-[B) (j) (ESC-[B)
     Move down a line in the buffer, or if already at the bottom line,
     move to the next event in the history list.

vi-down-line-or-history (unbound) (+) (unbound)
     Move down a line in the buffer, or if already at the bottom line,
     move to the next event in the history list.  Then move to the
     first non-blank character on the line.

down-line-or-search
     Move down a line in the buffer, or if already at the bottom line,
     search forward in the history for a line beginning with the first
     word in the buffer.

     If called from a function by the zle command with arguments, the
     first argument is taken as the string for which to search, rather
     than the first word in the buffer.

down-history (unbound) (^N) (unbound)
     Move to the next event in the history list.

history-beginning-search-backward
     Search backward in the history for a line beginning with the
     current line up to the cursor.  This leaves the cursor in its
     original position.

end-of-buffer-or-history (ESC->) (unbound) (unbound)
     Move to the end of the buffer, or if already there, move to the
     last event in the history list.

end-of-line-hist
     Move to the end of the line.  If already at the end of the buffer,
     move to the next history line.

end-of-history
     Move to the last event in the history list.

vi-fetch-history (unbound) (G) (unbound)
     Fetch the history line specified by the numeric argument.  This
     defaults to the current history line (i.e. the one that isn't
     history yet).

history-incremental-search-backward (^R ^Xr) (unbound) (unbound)
     Search backward incrementally for a specified string.  The search
     is case-insensitive if the search string does not have uppercase
     letters and no numeric argument was given.  The string may begin
     with `^' to anchor the search to the beginning of the line.  When
     called from a user-defined function returns the following
     statuses: 0, if the search succeeded; 1, if the search failed; 2,
     if the search term was a bad pattern; 3, if the search was aborted
     by the send-break command.

     A restricted set of editing functions is available in the
     mini-buffer.  Keys are looked up in the special isearch keymap,
     and if not found there in the main keymap (note that by default
     the isearch keymap is empty).  An interrupt signal, as defined by
     the stty setting, will stop the search and go back to the original
     line.  An undefined key will have the same effect.  Note that the
     following always perform the same task within incremental searches
     and cannot be replaced by user defined widgets, nor can the set of
     functions be extended.  The supported functions are:


    accept-and-hold
    accept-and-infer-next-history
    accept-line
    accept-line-and-down-history
          Perform the usual function after exiting incremental search.
          The command line displayed is executed.

    backward-delete-char
    vi-backward-delete-char
          Back up one place in the search history.  If the search has
          been repeated this does not immediately erase a character in
          the minibuffer.

    accept-search
          Exit incremental search, retaining the command line but
          performing no further action.  Note that this function is not
          bound by default and has no effect outside incremental search.

    backward-delete-word
    backward-kill-word
    vi-backward-kill-word
          Back up one character in the minibuffer; if multiple searches
          have been performed since the character was inserted the
          search history is rewound to the point just before the
          character was entered.  Hence this has the effect of repeating
          backward-delete-char.

    clear-screen
          Clear the screen, remaining in incremental search mode.

    history-incremental-search-backward
          Find the next occurrence of the contents of the mini-buffer.

    history-incremental-search-forward
          Invert the sense of the search.

    magic-space
          Inserts a non-magical space.

    quoted-insert
    vi-quoted-insert
          Quote the character to insert into the minibuffer.

    redisplay
          Redisplay the command line, remaining in incremental search
          mode.

    vi-cmd-mode
          Toggle between the `main' and `vicmd' keymaps; the `main'
          keymap (insert mode) will be selected initially.

    vi-repeat-search
    vi-rev-repeat-search
          Repeat the search.  The direction of the search is indicated
          in the mini-buffer.


     Any character that is not bound to one of the above functions, or
     self-insert or self-insert-unmeta, will cause the mode to be
     exited.  The character is then looked up and executed in the
     keymap in effect at that point.

     When called from a widget function by the zle command, the
     incremental search commands can take a string argument.  This will
     be treated as a string of keys, as for arguments to the bindkey
     command, and used as initial input for the command.  Any
     characters in the string which are unused by the incremental
     search will be silently ignored.  For example,


          zle history-incremental-search-backward forceps

     will search backwards for forceps, leaving the minibuffer
     containing the string `forceps'.

history-incremental-search-forward (^S ^Xs) (unbound) (unbound)
     Search forward incrementally for a specified string.  The search is
     case-insensitive if the search string does not have uppercase
     letters and no numeric argument was given.  The string may begin
     with `^' to anchor the search to the beginning of the line.  The
     functions available in the mini-buffer are the same as for
     history-incremental-search-backward.

history-incremental-pattern-search-backward
history-incremental-pattern-search-forward
     These widgets behave similarly to the corresponding widgets with
     no -pattern, but the search string typed by the user is treated as
     a pattern, respecting the current settings of the various options
     affecting pattern matching.  See *note Filename Generation:: for a
     description of patterns.  If no numeric argument was given
     lowercase letters in the search string may match uppercase letters
     in the history.  The string may begin with `^' to anchor the
     search to the beginning of the line.

     The prompt changes to indicate an invalid pattern; this may simply
     indicate the pattern is not yet complete.

     Note that only non-overlapping matches are reported, so an
     expression with wildcards may return fewer matches on a line than
     are visible by inspection.

history-search-backward (ESC-P ESC-p) (unbound) (unbound)
     Search backward in the history for a line beginning with the first
     word in the buffer.

     If called from a function by the zle command with arguments, the
     first argument is taken as the string for which to search, rather
     than the first word in the buffer.

vi-history-search-backward (unbound) (/) (unbound)
     Search backward in the history for a specified string.  The string
     may begin with `^' to anchor the search to the beginning of the
     line.

     A restricted set of editing functions is available in the
     mini-buffer.  An interrupt signal, as defined by the stty setting,
     will stop the search.  The functions available in the mini-buffer
     are: accept-line, backward-delete-char, vi-backward-delete-char,
     backward-kill-word, vi-backward-kill-word, clear-screen, redisplay,
     quoted-insert and vi-quoted-insert.

     vi-cmd-mode is treated the same as accept-line, and magic-space is
     treated as a space.  Any other character that is not bound to
     self-insert or self-insert-unmeta will beep and be ignored. If the
     function is called from vi command mode, the bindings of the
     current insert mode will be used.

     If called from a function by the zle command with arguments, the
     first argument is taken as the string for which to search, rather
     than the first word in the buffer.

history-search-forward (ESC-N ESC-n) (unbound) (unbound)
     Search forward in the history for a line beginning with the first
     word in the buffer.

     If called from a function by the zle command with arguments, the
     first argument is taken as the string for which to search, rather
     than the first word in the buffer.

vi-history-search-forward (unbound) (?) (unbound)
     Search forward in the history for a specified string.  The string
     may begin with `^' to anchor the search to the beginning of the
     line. The functions available in the mini-buffer are the same as
     for vi-history-search-backward.  Argument handling is also the same
     as for that command.

infer-next-history (^X^N) (unbound) (unbound)
     Search in the history list for a line matching the current one and
     fetch the event following it.

insert-last-word (ESC-_ ESC-.) (unbound) (unbound)
     Insert the last word from the previous history event at the cursor
     position.  If a positive numeric argument is given, insert that
     word from the end of the previous history event.  If the argument
     is zero or negative insert that word from the left (zero inserts
     the previous command word).  Repeating this command replaces the
     word just inserted with the last word from the history event prior
     to the one just used; numeric arguments can be used in the same
     way to pick a word from that event.

     When called from a shell function invoked from a user-defined
     widget, the command can take one to three arguments.  The first
     argument specifies a history offset which applies to successive
     calls to this widget: if it is -1, the default behaviour is used,
     while if it is 1, successive calls will move forwards through the
     history.  The value 0 can be used to indicate that the history
     line examined by the previous execution of the command will be
     reexamined.  Note that negative numbers should be preceded by a
     `--' argument to avoid confusing them with options.

     If two arguments are given, the second specifies the word on the
     command line in normal array index notation (as a more natural
     alternative to the prefix argument).  Hence 1 is the first word,
     and -1 (the default) is the last word.

     If a third argument is given, its value is ignored, but it is used
     to signify that the history offset is relative to the current
     history line, rather than the one remembered after the previous
     invocations of insert-last-word.

     For example, the default behaviour of the command corresponds to


          zle insert-last-word -- -1 -1

     while the command


          zle insert-last-word -- -1 1 -

     always copies the first word of the line in the history
     immediately before the line being edited.  This has the side
     effect that later invocations of the widget will be relative to
     that line.

vi-repeat-search (unbound) (n) (unbound)
     Repeat the last vi history search.

vi-rev-repeat-search (unbound) (N) (unbound)
     Repeat the last vi history search, but in reverse.

up-line-or-history (^P ESC-[A) (k) (ESC-[A)
     Move up a line in the buffer, or if already at the top line, move
     to the previous event in the history list.

vi-up-line-or-history (unbound) (-) (unbound)
     Move up a line in the buffer, or if already at the top line, move
     to the previous event in the history list.  Then move to the first
     non-blank character on the line.

up-line-or-search
     Move up a line in the buffer, or if already at the top line,
     search backward in the history for a line beginning with the first
     word in the buffer.

     If called from a function by the zle command with arguments, the
     first argument is taken as the string for which to search, rather
     than the first word in the buffer.

up-history (unbound) (^P) (unbound)
     Move to the previous event in the history list.

history-beginning-search-forward
     Search forward in the history for a line beginning with the current
     line up to the cursor.  This leaves the cursor in its original
     position.


File: zsh.info,  Node: Modifying Text,  Next: Arguments,  Prev: History Control,  Up: Zle Widgets

18.6.3 Modifying Text
---------------------


vi-add-eol (unbound) (A) (unbound)
     Move to the end of the line and enter insert mode.

vi-add-next (unbound) (a) (unbound)
     Enter insert mode after the current cursor position, without
     changing lines.

backward-delete-char (^H ^?) (unbound) (unbound)
     Delete the character behind the cursor.

vi-backward-delete-char (unbound) (X) (^H)
     Delete the character behind the cursor, without changing lines.
     If in insert mode, this won't delete past the point where insert
     mode was last entered.

backward-delete-word
     Delete the word behind the cursor.

backward-kill-line
     Kill from the beginning of the line to the cursor position.

backward-kill-word (^W ESC-^H ESC-^?) (unbound) (unbound)
     Kill the word behind the cursor.

vi-backward-kill-word (unbound) (unbound) (^W)
     Kill the word behind the cursor, without going past the point
     where insert mode was last entered.

capitalize-word (ESC-C ESC-c) (unbound) (unbound)
     Capitalize the current word and move past it.

vi-change (unbound) (c) (unbound)
     Read a movement command from the keyboard, and kill from the
     cursor position to the endpoint of the movement.  Then enter
     insert mode.  If the command is vi-change, change the current line.

vi-change-eol (unbound) (C) (unbound)
     Kill to the end of the line and enter insert mode.

vi-change-whole-line (unbound) (S) (unbound)
     Kill the current line and enter insert mode.

copy-region-as-kill (ESC-W ESC-w) (unbound) (unbound)
     Copy the area from the cursor to the mark to the kill buffer.

     If called from a ZLE widget function in the form `zle
     copy-region-as-kill STRING' then STRING will be taken as the text
     to copy to the kill buffer.  The cursor, the mark and the text on
     the command line are not used in this case.

copy-prev-word (ESC-^_) (unbound) (unbound)
     Duplicate the word to the left of the cursor.

copy-prev-shell-word
     Like copy-prev-word, but the word is found by using shell parsing,
     whereas copy-prev-word looks for blanks. This makes a difference
     when the word is quoted and contains spaces.

vi-delete (unbound) (d) (unbound)
     Read a movement command from the keyboard, and kill from the
     cursor position to the endpoint of the movement.  If the command
     is vi-delete, kill the current line.

delete-char
     Delete the character under the cursor.

vi-delete-char (unbound) (x) (unbound)
     Delete the character under the cursor, without going past the end
     of the line.

delete-word
     Delete the current word.

down-case-word (ESC-L ESC-l) (unbound) (unbound)
     Convert the current word to all lowercase and move past it.

kill-word (ESC-D ESC-d) (unbound) (unbound)
     Kill the current word.

gosmacs-transpose-chars
     Exchange the two characters behind the cursor.

vi-indent (unbound) (>) (unbound)
     Indent a number of lines.

vi-insert (unbound) (i) (unbound)
     Enter insert mode.

vi-insert-bol (unbound) (I) (unbound)
     Move to the first non-blank character on the line and enter insert
     mode.

vi-join (^X^J) (J) (unbound)
     Join the current line with the next one.

kill-line (^K) (unbound) (unbound)
     Kill from the cursor to the end of the line.  If already on the
     end of the line, kill the newline character.

vi-kill-line (unbound) (unbound) (^U)
     Kill from the cursor back to wherever insert mode was last entered.

vi-kill-eol (unbound) (D) (unbound)
     Kill from the cursor to the end of the line.

kill-region
     Kill from the cursor to the mark.

kill-buffer (^X^K) (unbound) (unbound)
     Kill the entire buffer.

kill-whole-line (^U) (unbound) (unbound)
     Kill the current line.

vi-match-bracket (^X^B) (%) (unbound)
     Move to the bracket character (one of {}, () or []) that matches
     the one under the cursor.  If the cursor is not on a bracket
     character, move forward without going past the end of the line to
     find one, and then go to the matching bracket.

vi-open-line-above (unbound) (O) (unbound)
     Open a line above the cursor and enter insert mode.

vi-open-line-below (unbound) (o) (unbound)
     Open a line below the cursor and enter insert mode.

vi-oper-swap-case
     Read a movement command from the keyboard, and swap the case of
     all characters from the cursor position to the endpoint of the
     movement.  If the movement command is vi-oper-swap-case, swap the
     case of all characters on the current line.

overwrite-mode (^X^O) (unbound) (unbound)
     Toggle between overwrite mode and insert mode.

vi-put-before (unbound) (P) (unbound)
     Insert the contents of the kill buffer before the cursor.  If the
     kill buffer contains a sequence of lines (as opposed to
     characters), paste it above the current line.

vi-put-after (unbound) (p) (unbound)
     Insert the contents of the kill buffer after the cursor.  If the
     kill buffer contains a sequence of lines (as opposed to
     characters), paste it below the current line.

quoted-insert (^V) (unbound) (unbound)
     Insert the next character typed into the buffer literally.  An
     interrupt character will not be inserted.

vi-quoted-insert (unbound) (unbound) (^Q ^V)
     Display a `^' at the cursor position, and insert the next
     character typed into the buffer literally.  An interrupt character
     will not be inserted.

quote-line (ESC-') (unbound) (unbound)
     Quote the current line; that is, put a `'' character at the
     beginning and the end, and convert all `'' characters to `'\'''.

quote-region (ESC-") (unbound) (unbound)
     Quote the region from the cursor to the mark.

vi-replace (unbound) (R) (unbound)
     Enter overwrite mode.

vi-repeat-change (unbound) (.) (unbound)
     Repeat the last vi mode text modification.  If a count was used
     with the modification, it is remembered.  If a count is given to
     this command, it overrides the remembered count, and is remembered
     for future uses of this command.  The cut buffer specification is
     similarly remembered.

vi-replace-chars (unbound) (r) (unbound)
     Replace the character under the cursor with a character read from
     the keyboard.

self-insert (printable characters) (unbound) (printable characters and some control characters)
     Insert a character into the buffer at the cursor position.

self-insert-unmeta (ESC-^I ESC-^J ESC-^M) (unbound) (unbound)
     Insert a character into the buffer after stripping the meta bit
     and converting ^M to ^J.

vi-substitute (unbound) (s) (unbound)
     Substitute the next character(s).

vi-swap-case (unbound) (~) (unbound)
     Swap the case of the character under the cursor and move past it.

transpose-chars (^T) (unbound) (unbound)
     Exchange the two characters to the left of the cursor if at end of
     line, else exchange the character under the cursor with the
     character to the left.

transpose-words (ESC-T ESC-t) (unbound) (unbound)
     Exchange the current word with the one before it.

vi-unindent (unbound) (<) (unbound)
     Unindent a number of lines.

up-case-word (ESC-U ESC-u) (unbound) (unbound)
     Convert the current word to all caps and move past it.

yank (^Y) (unbound) (unbound)
     Insert the contents of the kill buffer at the cursor position.

yank-pop (ESC-y) (unbound) (unbound)
     Remove the text just yanked, rotate the kill-ring (the history of
     previously killed text) and yank the new top.  Only works following
     yank or yank-pop.

vi-yank (unbound) (y) (unbound)
     Read a movement command from the keyboard, and copy the region
     from the cursor position to the endpoint of the movement into the
     kill buffer.  If the command is vi-yank, copy the current line.

vi-yank-whole-line (unbound) (Y) (unbound)
     Copy the current line into the kill buffer.

vi-yank-eol
     Copy the region from the cursor position to the end of the line
     into the kill buffer.  Arguably, this is what Y should do in vi,
     but it isn't what it actually does.


File: zsh.info,  Node: Arguments,  Next: Completion,  Prev: Modifying Text,  Up: Zle Widgets

18.6.4 Arguments
----------------


digit-argument (ESC-0..ESC-9) (1-9) (unbound)
     Start a new numeric argument, or add to the current one.  See also
     vi-digit-or-beginning-of-line.  This only works if bound to a key
     sequence ending in a decimal digit.

     Inside a widget function, a call to this function treats the last
     key of the key sequence which called the widget as the digit.

neg-argument (ESC--) (unbound) (unbound)
     Changes the sign of the following argument.

universal-argument
     Multiply the argument of the next command by 4.  Alternatively, if
     this command is followed by an integer (positive or negative), use
     that as the argument for the next command.  Thus digits cannot be
     repeated using this command.  For example, if this command occurs
     twice, followed immediately by forward-char, move forward sixteen
     spaces; if instead it is followed by -2, then forward-char, move
     backward two spaces.

     Inside a widget function, if passed an argument, i.e. `zle
     universal-argument NUM', the numerical argument will be set to
     NUM; this is equivalent to `NUMERIC=NUM'.

argument-base
     Use the existing numeric argument as a numeric base, which must be
     in the range 2 to 36 inclusive.  Subsequent use of digit-argument
     and universal-argument will input a new prefix in the given base.
     The usual hexadecimal convention is used: the letter a or A
     corresponds to 10, and so on.  Arguments in bases requiring digits
     from 10 upwards are more conveniently input with
     universal-argument, since ESC-a etc. are not usually bound to
     digit-argument.

     The function can be used with a command argument inside a
     user-defined widget.  The following code sets the base to 16 and
     lets the user input a hexadecimal argument until a key out of the
     digit range is typed:


          zle argument-base 16
          zle universal-argument


File: zsh.info,  Node: Completion,  Next: Miscellaneous,  Prev: Arguments,  Up: Zle Widgets

18.6.5 Completion
-----------------


accept-and-menu-complete
     In a menu completion, insert the current completion into the
     buffer, and advance to the next possible completion.

complete-word
     Attempt completion on the current word.

delete-char-or-list (^D) (unbound) (unbound)
     Delete the character under the cursor.  If the cursor is at the
     end of the line, list possible completions for the current word.

expand-cmd-path
     Expand the current command to its full pathname.

expand-or-complete (TAB) (unbound) (TAB)
     Attempt shell expansion on the current word.  If that fails,
     attempt completion.

expand-or-complete-prefix
     Attempt shell expansion on the current word up to cursor.

expand-history (ESC-space ESC-!) (unbound) (unbound)
     Perform history expansion on the edit buffer.

expand-word (^X*) (unbound) (unbound)
     Attempt shell expansion on the current word.

list-choices (ESC-^D) (^D =) (^D)
     List possible completions for the current word.

list-expand (^Xg ^XG) (^G) (^G)
     List the expansion of the current word.

magic-space
     Perform history expansion and insert a space into the buffer.
     This is intended to be bound to space.

menu-complete
     Like complete-word, except that menu completion is used.  See the
     MENU_COMPLETE option.

menu-expand-or-complete
     Like expand-or-complete, except that menu completion is used.

reverse-menu-complete
     Perform menu completion, like menu-complete, except that if a menu
     completion is already in progress, move to the _previous_
     completion rather than the next.

end-of-list
     When a previous completion displayed a list below the prompt, this
     widget can be used to move the prompt below the list.


File: zsh.info,  Node: Miscellaneous,  Prev: Completion,  Up: Zle Widgets

18.6.6 Miscellaneous
--------------------


accept-and-hold (ESC-A ESC-a) (unbound) (unbound)
     Push the contents of the buffer on the buffer stack and execute it.

accept-and-infer-next-history
     Execute the contents of the buffer.  Then search the history list
     for a line matching the current one and push the event following
     onto the buffer stack.

accept-line (^J ^M) (^J ^M) (^J ^M)
     Finish editing the buffer.  Normally this causes the buffer to be
     executed as a shell command.

accept-line-and-down-history (^O) (unbound) (unbound)
     Execute the current line, and push the next history event on the
     the buffer stack.

auto-suffix-remove
     If the previous action added a suffix (space, slash, etc.) to the
     word on the command line, remove it.  Otherwise do nothing.
     Removing the suffix ends any active menu completion or menu
     selection.

     This widget is intended to be called from user-defined widgets to
     enforce a desired suffix-removal behavior.

auto-suffix-retain
     If the previous action added a suffix (space, slash, etc.) to the
     word on the command line, force it to be preserved.  Otherwise do
     nothing.  Retaining the suffix ends any active menu completion or
     menu selection.

     This widget is intended to be called from user-defined widgets to
     enforce a desired suffix-preservation behavior.

beep
     Beep, unless the BEEP option is unset.

vi-cmd-mode (^X^V) (unbound) (^[)
     Enter command mode; that is, select the `vicmd' keymap.  Yes, this
     is bound by default in emacs mode.

vi-caps-lock-panic
     Hang until any lowercase key is pressed.  This is for vi users
     without the mental capacity to keep track of their caps lock key
     (like the author).

clear-screen (^L ESC-^L) (^L) (^L)
     Clear the screen and redraw the prompt.

describe-key-briefly
     Reads a key sequence, then prints the function bound to that
     sequence.

exchange-point-and-mark (^X^X) (unbound) (unbound)
     Exchange the cursor position (point) with the position of the mark.
     Unless a negative prefix argument is given, the region between
     point and mark is activated so that it can be highlighted.  If a
     zero prefix argument is given, the region is activated but point
     and mark are not swapped.

execute-named-cmd (ESC-x) (:) (unbound)
     Read the name of an editor command and execute it.  A restricted
     set of editing functions is available in the mini-buffer.  Keys
     are looked up in the special command keymap, and if not found
     there in the main keymap.  An interrupt signal, as defined by the
     stty setting, will abort the function.  Note that the following
     always perform the same task within the executed-named-cmd
     environment and cannot be replaced by user defined widgets, nor
     can the set of functions be extended.  The allowed functions are:
     backward-delete-char, vi-backward-delete-char, clear-screen,
     redisplay, quoted-insert, vi-quoted-insert, backward-kill-word,
     vi-backward-kill-word, kill-whole-line, vi-kill-line,
     backward-kill-line, list-choices, delete-char-or-list,
     complete-word, accept-line, expand-or-complete and
     expand-or-complete-prefix.

     kill-region kills the last word, and vi-cmd-mode is treated the
     same as accept-line.  The space and tab characters, if not bound
     to one of these functions, will complete the name and then list the
     possibilities if the AUTO_LIST option is set.  Any other character
     that is not bound to self-insert or self-insert-unmeta will beep
     and be ignored.  The bindings of the current insert mode will be
     used.

     Currently this command may not be redefined or called by name.

execute-last-named-cmd (ESC-z) (unbound) (unbound)
     Redo the last function executed with execute-named-cmd.

     Currently this command may not be redefined or called by name.

get-line (ESC-G ESC-g) (unbound) (unbound)
     Pop the top line off the buffer stack and insert it at the cursor
     position.

pound-insert (unbound) (#) (unbound)
     If there is no # character at the beginning of the buffer, add one
     to the beginning of each line.  If there is one, remove a # from
     each line that has one.  In either case, accept the current line.
     The INTERACTIVE_COMMENTS option must be set for this to have any
     usefulness.

vi-pound-insert
     If there is no # character at the beginning of the current line,
     add one.  If there is one, remove it.  The INTERACTIVE_COMMENTS
     option must be set for this to have any usefulness.

push-input
     Push the entire current multiline construct onto the buffer stack
     and return to the top-level (PS1) prompt.  If the current parser
     construct is only a single line, this is exactly like push-line.
     Next time the editor starts up or is popped with get-line, the
     construct will be popped off the top of the buffer stack and loaded
     into the editing buffer.

push-line (^Q ESC-Q ESC-q) (unbound) (unbound)
     Push the current buffer onto the buffer stack and clear the buffer.
     Next time the editor starts up, the buffer will be popped off the
     top of the buffer stack and loaded into the editing buffer.

push-line-or-edit
     At the top-level (PS1) prompt, equivalent to push-line.  At a
     secondary (PS2) prompt, move the entire current multiline
     construct into the editor buffer.  The latter is equivalent to
     push-input followed by get-line.

read-command
     Only useful from a user-defined widget.  A keystroke is read just
     as in normal operation, but instead of the command being executed
     the name of the command that would be executed is stored in the
     shell parameter REPLY.  This can be used as the argument of a
     future zle command.  If the key sequence is not bound, status 1 is
     returned; typically, however, REPLY is set to undefined-key to
     indicate a useless key sequence.

recursive-edit
     Only useful from a user-defined widget.  At this point in the
     function, the editor regains control until one of the standard
     widgets which would normally cause zle to exit (typically an
     accept-line caused by hitting the return key) is executed.
     Instead, control returns to the user-defined widget.  The status
     returned is non-zero if the return was caused by an error, but the
     function still continues executing and hence may tidy up.  This
     makes it safe for the user-defined widget to alter the command
     line or key bindings temporarily.

     The following widget, caps-lock, serves as an example.
          self-insert-ucase() {
            LBUFFER+=${(U)KEYS[-1]}
          }

          integer stat

          zle -N self-insert self-insert-ucase
          zle -A caps-lock save-caps-lock
          zle -A accept-line caps-lock

          zle recursive-edit
          stat=$?

          zle -A .self-insert self-insert
          zle -A save-caps-lock caps-lock
          zle -D save-caps-lock

          (( stat )) && zle send-break

          return $stat
     This causes typed letters to be inserted capitalised until either
     accept-line (i.e. typically the return key) is typed or the
     caps-lock widget is invoked again; the later is handled by saving
     the old definition of caps-lock as save-caps-lock and then
     rebinding it to invoke accept-line.  Note that an error from the
     recursive edit is detected as a non-zero return status and
     propagated by using the send-break widget.

redisplay (unbound) (^R) (^R)
     Redisplays the edit buffer.

reset-prompt (unbound) (unbound) (unbound)
     Force the prompts on both the left and right of the screen to be
     re-expanded, then redisplay the edit buffer.  This reflects
     changes both to the prompt variables themselves and changes in the
     expansion of the values (for example, changes in time or
     directory, or changes to the value of variables referred to by the
     prompt).

     Otherwise, the prompt is only expanded each time zle starts, and
     when the display as been interrupted by output from another part
     of the shell (such as a job notification) which causes the command
     line to be reprinted.

send-break (^G ESC-^G) (unbound) (unbound)
     Abort the current editor function, e.g. execute-named-command, or
     the editor itself, e.g. if you are in vared. Otherwise abort the
     parsing of the current line; in this case the aborted line is
     available in the shell variable ZLE_LINE_ABORTED.

run-help (ESC-H ESC-h) (unbound) (unbound)
     Push the buffer onto the buffer stack, and execute the command
     `run-help CMD', where CMD is the current command.  run-help is
     normally aliased to man.

vi-set-buffer (unbound) (") (unbound)
     Specify a buffer to be used in the following command.  There are
     35 buffers that can be specified: the 26 `named' buffers "a to "z
     and the nine `queued' buffers "1 to "9.  The named buffers can also
     be specified as "A to "Z.

     When a buffer is specified for a cut command, the text being cut
     replaces the previous contents of the specified buffer.  If a
     named buffer is specified using a capital, the newly cut text is
     appended to the buffer instead of overwriting it.

     If no buffer is specified for a cut command, "1 is used, and the
     contents of "1 to "8 are each shifted along one buffer; the
     contents of "9 is lost.

vi-set-mark (unbound) (m) (unbound)
     Set the specified mark at the cursor position.

set-mark-command (^@) (unbound) (unbound)
     Set the mark at the cursor position.  If called with a negative
     prefix argument, do not set the mark but deactivate the region so
     that it is no longer highlighted (it is still usable for other
     purposes).  Otherwise the region is marked as active.

spell-word (ESC-$ ESC-S ESC-s) (unbound) (unbound)
     Attempt spelling correction on the current word.

undefined-key
     This command is executed when a key sequence that is not bound to
     any command is typed.  By default it beeps.

undo (^_ ^Xu ^X^U) (unbound) (unbound)
     Incrementally undo the last text modification.

redo
     Incrementally redo undone text modifications.

vi-undo-change (unbound) (u) (unbound)
     Undo the last text modification.  If repeated, redo the
     modification.

what-cursor-position (^X=) (unbound) (unbound)
     Print the character under the cursor, its code as an octal,
     decimal and hexadecimal number, the current cursor position within
     the buffer and the column of the cursor in the current line.

where-is
     Read the name of an editor command and and print the listing of key
     sequences that invoke the specified command.  A restricted set of
     editing functions is available in the mini-buffer.  Keys are
     looked up in the special command keymap, and if not found there in
     the main keymap.

which-command (ESC-?) (unbound) (unbound)
     Push the buffer onto the buffer stack, and execute the command
     `which-command CMD'. where CMD is the current command.
     which-command is normally aliased to WHENCE.

vi-digit-or-beginning-of-line (unbound) (0) (unbound)
     If the last command executed was a digit as part of an argument,
     continue the argument.  Otherwise, execute vi-beginning-of-line.



File: zsh.info,  Node: Character Highlighting,  Prev: Zle Widgets,  Up: Zsh Line Editor

18.7 Character Highlighting
===========================

The line editor has the ability to highlight characters or regions of
the line that have a particular significance.  This is controlled by
the array parameter zle_highlight, if it has been set by the user.

If the parameter contains the single entry none all highlighting is
turned off.  Note the parameter is still expected to be an array.

Otherwise each entry of the array should consist of a word indicating a
context for highlighting, then a colon, then a comma-separated list of
the types of highlighting to apply in that context.

The contexts available for highlighting are the following:


default
     Any text within the command line not affected by any other
     highlighting.  Text outside the editable area of the command line
     is not affected.

isearch
     When one of the incremental history search widgets is active, the
     area of the command line matched by the search string or pattern.

region
     The region between the cursor (point) and the mark as set with
     set-mark-command.  The region is only highlighted if it is active,
     which is the case if set-mark-command or exchange-point-and-mark
     has been called and the line has not been subsequently modified.
     The region can be deactivated by calling set-mark-command with a
     negative prefix argument, or reactivated by calling
     exchange-point-and-mark with a zero prefix argument.  Note that
     whether or not the region is active has no effect on its use
     within widgets, it simply determines whether it is highlighted.

special
     Individual characters that have no direct printable representation
     but are shown in a special manner by the line editor.  These
     characters are described below.

suffix
     This context is used in completion for characters that are marked
     as suffixes that will be removed if the completion ends at that
     point, the most obvious example being a slash (/) after a
     directory name.  Note that suffix removal is configurable; the
     circumstances under which the suffix will be removed may differ
     for different completions.


zle_highlight may contain additional fields for controlling how
terminal sequences to change colours are output.  Each of the following
is followed by a colon and a string in the same form as for key
bindings.  This will not be necessary for the vast majority of
terminals as the defaults shown in parentheses are widely used.


fg_start_code (\e[3)
     The start of the escape sequence for the foreground colour.  This
     is followed by an ASCII digit representing the colour.

fg_default_code (9)
     The number to use instead of the colour to reset the default
     foreground colour.

fg_end_code (m)
     The end of the escape sequence for the foreground colour.

bg_start_code (\e[4)
     The start of the escape sequence for the background colour.  This
     is followed by an ASCII digit representing the colour.

bg_default_code (9)
     The number to use instead of the colour to reset the default
     background colour.

bg_end_code (m)
     The end of the escape sequence for the background colour.


The available types of highlighting are the following.  Note that not
all types of highlighting are available on all terminals:


none
     No highlighting is applied to the given context.  It is not useful
     for this to appear with other types of highlighting; it is used to
     override a default.

fg=COLOUR
     The foreground colour should be set to COLOUR, a decimal integer
     or the name of one of the eight most widely-supported colours.

     Not all terminals support this and, of those that do, not all
     provide facilities to test the support, hence the user should
     decide based on the terminal type.  Most terminals support the
     colours black, red, green, yellow, blue, magenta, cyan and white,
     which can be set by name.  In addition. default may be used to set
     the terminal's default foreground colour.  Abbreviations are
     allowed; b or bl selects black.  Some terminals may generate
     additional colours if the bold attribute is also present.

     On recent terminals and on systems with an up-to-date terminal
     database the number of colours supported may be tested by the
     command `echotc Co'; if this succeeds, it indicates a limit on the
     number of colours which will be enforced by the line editor.  The
     number of colours is in any case limited to 256 (i.e. the range 0
     to 255).

     Colour is also known as color.

bg=COLOUR
     The background colour should be set to COLOUR.  This works
     similarly to the foreground colour, except the background is not
     usually affected by the bold attribute.

bold
     The characters in the given context are shown in a bold font.  Not
     all terminals distinguish bold fonts.

standout
     The characters in the given context are shown in the terminal's
     standout mode.  The actual effect is specific to the terminal; on
     many terminals it is inverse video.  On some such terminals, where
     the cursor does not blink it appears with standout mode negated,
     making it less than clear where the cursor actually is.  On such
     terminals one of the other effects may be preferable for
     highlighting the region and matched search string.

underline
     The characters in the given context are shown underlined.  Some
     terminals show the foreground in a different colour instead; in
     this case whitespace will not be highlighted.


The characters described above as `special' are as follows.  The
formatting described here is used irrespective of whether the characters
are highlighted:


ASCII control characters
     Control characters in the ASCII range are shown as `^' followed by
     the base character.

Unprintable multibyte characters
     This item applies to control characters not in the ASCII range,
     plus other characters as follows.  If the MULTIBYTE option is in
     effect, multibyte characters not in the ASCII character set that
     are reported as having zero width are treated as combining
     characters when the option COMBINING_CHARS is on.  If the option
     is off, or if a character appears where a combining character is
     not valid, the character is treated as unprintable.

     Unprintable multibyte characters are shown as a hexadecimal number
     between angle brackets.  The number is the code point of the
     character in the wide character set; this may or may not be
     Unicode, depending on the operating system.

Invalid multibyte characters
     If the MULTIBYTE option is in effect, any sequence of one or more
     bytes that does not form a valid character in the current character
     set is treated as a series of bytes each shown as a special
     character.  This case can be distinguished from other unprintable
     characters as the bytes are represented as two hexadecimal digits
     between angle brackets, as distinct from the four or eight digits
     that are used for unprintable characters that are nonetheless
     valid in the current character set.

     Not all systems support this: for it to work, the system's
     representation of wide characters must be code values from the
     Universal Character Set, as defined by IS0 10646 (also known as
     Unicode).


If zle_highlight is not set or no value applies to a particular
context, the defaults applied are equivalent to


     zle_highlight=(region:standout special:standout
     suffix:bold isearch:underline)

i.e. both the region and special characters are shown in standout mode.

Within widgets, arbitrary regions may be highlighted by setting the
special array parameter region_highlight; see *note Zle Widgets::.



File: zsh.info,  Node: Completion Widgets,  Next: Completion System,  Prev: Zsh Line Editor,  Up: Top

19 Completion Widgets
*********************



19.1 Description
================

The shell's programmable completion mechanism can be manipulated in two
ways; here the low-level features supporting the newer, function-based
mechanism are defined.  A complete set of shell functions based on these
features is described in the next chapter, *note Completion System::,
and users with no interest in adding to that system (or, potentially,
writing their own -- see dictionary entry for `hubris') should skip the
current section.  The older system based on the compctl builtin command
is described in *note Completion Using compctl::.

Completion widgets are defined by the -C option to the zle builtin
command provided by the zsh/zle module (see *note The zsh/zle
Module::). For example,


     zle -C complete expand-or-complete completer

defines a widget named `complete'.  The second argument is the name of
any of the builtin widgets that handle completions: complete-word,
expand-or-complete, expand-or-complete-prefix, menu-complete,
menu-expand-or-complete, reverse-menu-complete, list-choices, or
delete-char-or-list.  Note that this will still work even if the widget
in question has been re-bound.

When this newly defined widget is bound to a key using the bindkey
builtin command defined in the zsh/zle module (*note Zsh Line
Editor::), typing that key will call the shell function `completer'.
This function is responsible for generating the possible matches using
the builtins described below.  As with other ZLE widgets, the function
is called with its standard input closed.

Once the function returns, the completion code takes over control again
and treats the matches in the same manner as the specified builtin
widget, in this case expand-or-complete.



* Menu:

* Completion Special Parameters::
* Completion Builtin Commands::
* Completion Condition Codes::
* Completion Matching Control::
* Completion Widget Example::


File: zsh.info,  Node: Completion Special Parameters,  Next: Completion Builtin Commands,  Up: Completion Widgets

19.2 Completion Special Parameters
==================================

The parameters ZLE_REMOVE_SUFFIX_CHARS and ZLE_SPACE_SUFFIX_CHARS are
used by the completion mechanism, but are not special.  *note
Parameters Used By The Shell::.

Inside completion widgets, and any functions called from them, some
parameters have special meaning; outside these functions they are not
special to the shell in any way.  These parameters are used to pass
information between the completion code and the completion widget. Some
of the builtin commands and the condition codes use or change the
current values of these parameters.  Any existing values will be hidden
during execution of completion widgets; except for compstate, the
parameters are reset on each function exit (including nested function
calls from within the completion widget) to the values they had when
the function was entered.


CURRENT
     This is the number of the current word, i.e. the word the cursor is
     currently on in the words array.  Note that this value is only
     correct if the ksharrays option is not set.

IPREFIX
     Initially this will be set to the empty string.  This parameter
     functions like PREFIX; it contains a string which precedes the one
     in PREFIX and is not considered part of the list of matches.
     Typically, a string is transferred from the beginning of PREFIX to
     the end of IPREFIX, for example:


          IPREFIX=${PREFIX%%\=*}=
          PREFIX=${PREFIX#*=}

     causes the part of the prefix up to and including the first equal
     sign not to be treated as part of a matched string.  This can be
     done automatically by the compset builtin, see below.

ISUFFIX
     As IPREFIX, but for a suffix that should not be considered part of
     the matches; note that the ISUFFIX string follows the SUFFIX
     string.

PREFIX
     Initially this will be set to the part of the current word from the
     beginning of the word up to the position of the cursor; it may be
     altered to give a common prefix for all matches.

QIPREFIX
     This parameter is read-only and contains the quoted string up to
     the word being completed. E.g. when completing `"foo', this
     parameter contains the double quote. If the -q option of compset
     is used (see below), and the original string was `"foo bar' with
     the cursor on the `bar', this parameter contains `"foo '.

QISUFFIX
     Like QIPREFIX, but containing the suffix.

SUFFIX
     Initially this will be set to the part of the current word from the
     cursor position to the end; it may be altered to give a common
     suffix for all matches.  It is most useful when the option
     COMPLETE_IN_WORD is set, as otherwise the whole word on the
     command line is treated as a prefix.

compstate
     This is an associative array with various keys and values that the
     completion code uses to exchange information with the completion
     widget.  The keys are:


    all_quotes
          The -q option of the compset builtin command (see below)
          allows a quoted string to be broken into separate words; if
          the cursor is on one of those words, that word will be
          completed, possibly invoking `compset -q' recursively.  With
          this key it is possible to test the types of quoted strings
          which are currently broken into parts in this fashion.  Its
          value contains one character for each quoting level.  The
          characters are a single quote or a double quote for strings
          quoted with these characters, a dollars sign for strings
          quoted with $'...' and a backslash for strings not starting
          with a quote character.  The first character in the value
          always corresponds to the innermost quoting level.

    context
          This will be set by the completion code to the overall context
          in which completion is attempted. Possible values are:


         array_value
               when completing inside the value of an array parameter
               assignment; in this case the words array contains the
               words inside the parentheses.

         brace_parameter
               when completing the name of a parameter in a parameter
               expansion beginning with ${.

         assign_parameter
               when completing the name of a parameter in a parameter
               assignment.

         command
               when completing for a normal command (either in command
               position or for an argument of the command).

         condition
               when completing inside a `[[...]]' conditional
               expression; in this case the words array contains only
               the words inside the conditional expression.

         math
               when completing in a mathematical environment such as a
               `((...))' construct.

         parameter
               when completing the name of a parameter in a parameter
               expansion beginning with $ but not ${.

         redirect
               when completing after a redirection operator.

         subscript
               when completing inside a parameter subscript.

         value
               when completing the value of a parameter assignment.


    exact
          Controls the behaviour when the REC_EXACT option is set.  It
          will be set to accept if an exact match would be accepted,
          and will be unset otherwise.

          If it was set when at least one match equal to the string on
          the line was generated, the match is accepted.

    exact_string
          The string of an exact match if one was found, otherwise
          unset.

    ignored
          The number of words that were ignored because they matched
          one of the patterns given with the -F option to the compadd
          builtin command.

    insert
          This controls the manner in which a match is inserted into
          the command line.  On entry to the widget function, if it is
          unset the command line is not to be changed; if set to
          unambiguous, any prefix common to all matches is to be
          inserted; if set to automenu-unambiguous, the common prefix
          is to be inserted and the next invocation of the completion
          code may start menu completion (due to the AUTO_MENU option
          being set); if set to menu or automenu menu completion will
          be started for the matches currently generated (in the latter
          case this will happen because the AUTO_MENU is set). The
          value may also contain the string `tab' when the completion
          code would normally not really do completion, but only insert
          the TAB character.

          On exit it may be set to any of the values above (where
          setting it to the empty string is the same as unsetting it),
          or to a number, in which case the match whose number is given
          will be inserted into the command line.  Negative numbers
          count backward from the last match (with `-1' selecting the
          last match) and out-of-range values are wrapped around, so
          that a value of zero selects the last match and a value one
          more than the maximum selects the first. Unless the value of
          this key ends in a space, the match is inserted as in a menu
          completion, i.e. without automatically appending a space.

          Both menu and automenu may also specify the the number of the
          match to insert, given after a colon.  For example, `menu:2'
          says to start menu completion, beginning with the second
          match.

          Note that a value containing the substring `tab' makes the
          matches generated be ignored and only the TAB be inserted.

          Finally, it may also be set to all, which makes all matches
          generated be inserted into the line.

    insert_positions
          When the completion system inserts an unambiguous string into
          the line, there may be multiple places where characters are
          missing or where the character inserted differs from at least
          one match.  The value of this key contains a colon separated
          list of all these positions, as indexes into the command line.

    last_prompt
          If this is set to a non-empty string for every match added,
          the completion code will move the cursor back to the previous
          prompt after the list of completions has been displayed.
          Initially this is set or unset according to the
          ALWAYS_LAST_PROMPT option.

    list
          This controls whether or how the list of matches will be
          displayed.  If it is unset or empty they will never be
          listed; if its value begins with list, they will always be
          listed; if it begins with autolist or ambiguous, they will be
          listed when the AUTO_LIST or LIST_AMBIGUOUS options
          respectively would normally cause them to be.

          If the substring force appears in the value, this makes the
          list be shown even if there is only one match. Normally, the
          list would be shown only if there are at least two matches.

          The value contains the substring packed if the LIST_PACKED
          option is set. If this substring is given for all matches
          added to a group, this group will show the LIST_PACKED
          behavior. The same is done for the LIST_ROWS_FIRST option
          with the substring rows.

          Finally, if the value contains the string explanations, only
          the explanation strings, if any, will be listed and if it
          contains messages, only the messages (added with the -x
          option of compadd) will be listed.  If it contains both
          explanations and messages both kinds of explanation strings
          will be listed.  It will be set appropriately on entry to a
          completion widget and may be changed there.

    list_lines
          This gives the number of lines that are needed to display the
          full list of completions.  Note that to calculate the total
          number of lines to display you need to add the number of
          lines needed for the command line to this value, this is
          available as the value of the BUFFERLINES special parameter.

    list_max
          Initially this is set to the value of the LISTMAX parameter.
          It may be set to any other value; when the widget exits this
          value will be used in the same way as the value of LISTMAX.

    nmatches
          The number of matches generated and accepted by the
          completion code so far.

    old_insert
          On entry to the widget this will be set to the number of the
          match of an old list of completions that is currently
          inserted into the command line. If no match has been
          inserted, this is unset.

          As with old_list, the value of this key will only be used if
          it is the string keep. If it was set to this value by the
          widget and there was an old match inserted into the command
          line, this match will be kept and if the value of the insert
          key specifies that another match should be inserted, this
          will be inserted after the old one.

    old_list
          This is set to yes if there is still a valid list of
          completions from a previous completion at the time the widget
          is invoked.  This will usually be the case if and only if the
          previous editing operation was a completion widget or one of
          the builtin completion functions.  If there is a valid list
          and it is also currently shown on the screen, the value of
          this key is shown.

          After the widget has exited the value of this key is only
          used if it was set to keep.  In this case the completion code
          will continue to use this old list.  If the widget generated
          new matches, they will not be used.

    parameter
          The name of the parameter when completing in a subscript or
          in the value of a parameter assignment.

    pattern_insert
          Normally this is set to menu, which specifies that menu
          completion will be used whenever a set of matches was
          generated using pattern matching.  If it is set to any other
          non-empty string by the user and menu completion is not
          selected by other option settings, the code will instead
          insert any common prefix for the generated matches as with
          normal completion.

    pattern_match
          Locally controls the behaviour given by the GLOB_COMPLETE
          option.  Initially it is set to `*' if and only if the option
          is set.  The completion widget may set it to this value, to
          an empty string (which has the same effect as unsetting it),
          or to any other non-empty string.  If it is non-empty,
          unquoted metacharacters on the command line will be treated
          as patterns; if it is `*', then additionally a wildcard `*'
          is assumed at the cursor position; if it is empty or unset,
          metacharacters will be treated literally.

          Note that the matcher specifications given to the compadd
          builtin command are not used if this is set to a non-empty
          string.

    quote
          When completing inside quotes, this contains the quotation
          character (i.e. either a single quote, a double quote, or a
          backtick).  Otherwise it is unset.

    quoting
          When completing inside single quotes, this is set to the
          string single; inside double quotes, the string double;
          inside backticks, the string backtick.  Otherwise it is unset.

    redirect
          The redirection operator when completing in a redirection
          position, i.e. one of <, >, etc.

    restore
          This is set to auto before a function is entered, which
          forces the special parameters mentioned above (words,
          CURRENT, PREFIX, IPREFIX, SUFFIX, and ISUFFIX) to be restored
          to their previous values when the function exits.   If a
          function unsets it or sets it to any other string, they will
          not be restored.

    to_end
          Specifies the occasions on which the cursor is moved to the
          end of a string when a match is inserted.  On entry to a
          widget function, it may be single if this will happen when a
          single unambiguous match was inserted or match if it will
          happen any time a match is inserted (for example, by menu
          completion; this is likely to be the effect of the
          ALWAYS_TO_END option).

          On exit, it may be set to single as above.  It may also be
          set to always, or to the empty string or unset; in those
          cases the cursor will be moved to the end of the string
          always or never respectively.  Any other string is treated as
          match.

    unambiguous
          This key is read-only and will always be set to the common
          (unambiguous) prefix the completion code has generated for
          all matches added so far.

    unambiguous_cursor
          This gives the position the cursor would be placed at if the
          common prefix in the unambiguous key were inserted, relative
          to the value of that key. The cursor would be placed before
          the character whose index is given by this key.

    unambiguous_positions
          This contains all positions where characters in the
          unambiguous string are missing or where the character
          inserted differs from at least one of the matches.  The
          positions are given as indexes into the string given by the
          value of the unambiguous key.

    vared
          If completion is called while editing a line using the vared
          builtin, the value of this key is set to the name of the
          parameter given as an argument to vared.  This key is only
          set while a vared command is active.


words
     This array contains the words present on the command line
     currently being edited.



File: zsh.info,  Node: Completion Builtin Commands,  Next: Completion Condition Codes,  Prev: Completion Special Parameters,  Up: Completion Widgets

19.3 Completion Builtin Commands
================================


compadd [ -akqQfenUld12C ] [ -F ARRAY ]
[ -P PREFIX ] [ -S SUFFIX ]
[ -p HIDDEN-PREFIX ] [ -s HIDDEN-SUFFIX ]
[ -i IGNORED-PREFIX ] [ -I IGNORED-SUFFIX ]
[ -W FILE-PREFIX ] [ -d ARRAY ]
[ -J NAME ] [ -V NAME ] [ -X EXPLANATION ] [ -x MESSAGE ]
[ -r REMOVE-CHARS ] [ -R REMOVE-FUNC ]
[ -D ARRAY ] [ -O ARRAY ] [ -A ARRAY ]
[ -E NUMBER ]
[ -M MATCH-SPEC ] [ -- ] [ WORDS ... ]
     This builtin command can be used to add matches directly and
     control all the information the completion code stores with each
     possible match. The return status is zero if at least one match
     was added and non-zero if no matches were added.

     The completion code breaks the string to complete into seven
     fields in the order:



          <IPRE><APRE><HPRE><WORD><HSUF><ASUF><ISUF>

     The first field is an ignored prefix taken from the command line,
     the contents of the IPREFIX parameter plus the string given with
     the -i option. With the -U option, only the string from the -i
     option is used. The field <APRE> is an optional prefix string
     given with the -P option.  The <HPRE> field is a string that is
     considered part of the match but that should not be shown when
     listing completions, given with the -p option; for example,
     functions that do filename generation might specify a common path
     prefix this way.  <WORD> is the part of the match that should
     appear in the list of completions, i.e. one of the WORDS given at
     the end of the compadd command line. The suffixes <HSUF>, <ASUF>
     and <ISUF> correspond to the prefixes <HPRE>, <APRE> and <IPRE>
     and are given by the options -s, -S and -I, respectively.

     The supported flags are:


    -P PREFIX
          This gives a string to be inserted before the given WORDS.
          The string given is not considered as part of the match and
          any shell metacharacters in it will not be quoted when the
          string is inserted.

    -S SUFFIX
          Like -P, but gives a string to be inserted after the match.

    -p HIDDEN-PREFIX
          This gives a string that should be inserted into the command
          line before the match but that should not appear in the list
          of matches. Unless the -U option is given, this string must
          be matched as part of the string on the command line.

    -s HIDDEN-SUFFIX
          Like `-p', but gives a string to insert after the match.

    -i IGNORED-PREFIX
          This gives a string to insert into the command line just
          before any string given with the `-P' option.  Without `-P'
          the string is inserted before the string given with `-p' or
          directly before the match.

    -I IGNORED-SUFFIX
          Like -i, but gives an ignored suffix.

    -a
          With this flag the WORDS are taken as names of arrays and the
          possible matches are their values.  If only some elements of
          the arrays are needed, the WORDS may also contain subscripts,
          as in `foo[2,-1]'.

    -k
          With this flag the WORDS are taken as names of associative
          arrays and the possible matches are their keys.  As for -a,
          the WORDS may also contain subscripts, as in `foo[(R)*bar*]'.

    -d ARRAY
          This adds per-match display strings. The ARRAY should contain
          one element per WORD given. The completion code will then
          display the first element instead of the first WORD, and so
          on. The ARRAY may be given as the name of an array parameter
          or directly as a space-separated list of words in parentheses.

          If there are fewer display strings than WORDS, the leftover
          WORDS will be displayed unchanged and if there are more
          display strings than WORDS, the leftover display strings will
          be silently ignored.

    -l
          This option only has an effect if used together with the -d
          option. If it is given, the display strings are listed one
          per line, not arrayed in columns.

    -o
          This option only has an effect if used together with the -d
          option.  If it is given, the order of the output is
          determined by the match strings;  otherwise it is determined
          by the display strings (i.e. the strings given by the -d
          option).

    -J NAME
          Gives the name of the group of matches the words should be
          stored in.

    -V NAME
          Like -J but naming an unsorted group. These are in a
          different name space than groups created with the -J flag.

    -1
          If given together with the -V option, makes only consecutive
          duplicates in the group be removed. If combined with the -J
          option, this has no visible effect. Note that groups with and
          without this flag are in different name spaces.

    -2
          If given together with the -J or -V option, makes all
          duplicates be kept. Again, groups with and without this flag
          are in different name spaces.

    -X EXPLANATION
          The EXPLANATION string will be printed with the list of
          matches, above the group currently selected.

    -x MESSAGE
          Like -X, but the MESSAGE will be printed even if there are no
          matches in the group.

    -q
          The suffix given with -S will be automatically removed if the
          next character typed is a blank or does not insert anything,
          or if the suffix consists of only one character and the next
          character typed is the same character.

    -r REMOVE-CHARS
          This is a more versatile form of the -q option.  The suffix
          given with -S or the slash automatically added after
          completing directories will be automatically removed if the
          next character typed inserts one of the characters given in
          the REMOVE-CHARS.  This string is parsed as a characters
          class and understands the backslash sequences used by the
          print command.  For example, `-r "a-z\t"' removes the suffix
          if the next character typed inserts a lower case character or
          a TAB, and `-r "^0-9"' removes the suffix if the next
          character typed inserts anything but a digit. One extra
          backslash sequence is understood in this string: `\-' stands
          for all characters that insert nothing. Thus `-S "=" -q' is
          the same as `-S "=" -r "= \t\n\-"'.

          This option may also be used without the -S option; then any
          automatically added space will be removed when one of the
          characters in the list is typed.

    -R REMOVE-FUNC
          This is another form of the -r option. When a suffix has been
          inserted and the completion accepted, the function
          REMOVE-FUNC will be called after the next character typed.
          It is passed the length of the suffix as an argument and can
          use the special parameters available in ordinary
          (non-completion) zle widgets (see *note Zsh Line Editor::) to
          analyse and modify the command line.

    -f
          If this flag is given, all of the matches built from WORDS are
          marked as being the names of files.  They are not required to
          be actual filenames, but if they are, and the option
          LIST_TYPES is set, the characters describing the types of the
          files in the completion lists will be shown. This also forces
          a slash to be added when the name of a directory is completed.

    -e
          This flag can be used to tell the completion code that the
          matches added are parameter names for a parameter expansion.
          This will make the AUTO_PARAM_SLASH and AUTO_PARAM_KEYS
          options be used for the matches.

    -W FILE-PREFIX
          This string is a pathname that will be prepended to each of
          the matches formed by the given WORDS together with any
          prefix specified by the -p option to form a complete filename
          for testing.  Hence it is only useful if combined with the -f
          flag, as the tests will not otherwise be performed.

    -F ARRAY
          Specifies an array containing patterns. Words matching one of
          these patterns are ignored, i.e. not considered to be
          possible matches.

          The ARRAY may be the name of an array parameter or a list of
          literal patterns enclosed in parentheses and quoted, as in
          `-F "(*?.o *?.h)"'. If the name of an array is given, the
          elements of the array are taken as the patterns.

    -Q
          This flag instructs the completion code not to quote any
          metacharacters in the words when inserting them into the
          command line.

    -M MATCH-SPEC
          This gives local match specifications as described below in
          *note Completion Matching Control::. This option may be given
          more than once.  In this case all MATCH-SPECs given are
          concatenated with spaces between them to form the
          specification string to use.  Note that they will only be
          used if the -U option is not given.

    -n
          Specifies that the words added are to be used as possible
          matches, but are not to appear in the completion listing.

    -U
          If this flag is given, all words given will be accepted and
          no matching will be done by the completion code. Normally
          this is used in functions that do the matching themselves.

    -O ARRAY
          If this option is given, the WORDS are _not_ added to the set
          of possible completions.  Instead, matching is done as usual
          and all of the WORDS given as arguments that match the string
          on the command line will be stored in the array parameter
          whose name is given as ARRAY.

    -A ARRAY
          As the -O option, except that instead of those of the WORDS
          which match being stored in ARRAY, the strings generated
          internally by the completion code are stored. For example,
          with a matching specification of `-M "L:|no="', the string
          `nof' on the command line and the string `foo' as one of the
          WORDS, this option stores the string `nofoo' in the array,
          whereas the -O option stores the `foo' originally given.

    -D ARRAY
          As with -O, the WORDS are not added to the set of possible
          completions.  Instead, the completion code tests whether each
          WORD in turn matches what is on the line.  If the Nth WORD
          does not match, the Nth element of the ARRAY is removed.
          Elements for which the corresponding WORD is matched are
          retained.

    -C
          This option adds a special match which expands to all other
          matches when inserted into the line, even those that are
          added after this option is used.  Together with the -d option
          it is possible to specify a string that should be displayed
          in the list for this special match.  If no string is given,
          it will be shown as a string containing the strings that
          would be inserted for the other matches, truncated to the
          width of the screen.

    -E
          This option adds NUMBER empty matches after the WORDS have
          been added.  An empty match takes up space in completion
          listings but will never be inserted in the line and can't be
          selected with menu completion or menu selection.  This makes
          empty matches only useful to format completion lists and to
          make explanatory string be shown in completion lists (since
          empty matches can be given display strings with the -d
          option).  And because all but one empty string would
          otherwise be removed, this option implies the -V and -2
          options (even if an explicit -J option is given).

    -
    --
          This flag ends the list of flags and options. All arguments
          after it will be taken as the words to use as matches even if
          they begin with hyphens.


     Except for the -M flag, if any of these flags is given more than
     once, the first one (and its argument) will be used.

compset -p NUMBER
compset -P [ NUMBER ] PATTERN
compset -s NUMBER
compset -S [ NUMBER ] PATTERN
compset -n BEGIN [ END ]
compset -N BEG-PAT [ END-PAT ]
compset -q
     This command simplifies modification of the special parameters,
     while its return status allows tests on them to be carried out.

     The options are:


    -p NUMBER
          If the contents of the PREFIX parameter is longer than NUMBER
          characters, the first NUMBER characters are removed from it
          and appended to the contents of the IPREFIX parameter.

    -P [ NUMBER ] PATTERN
          If the value of the PREFIX parameter begins with anything that
          matches the PATTERN, the matched portion is removed from
          PREFIX and appended to IPREFIX.

          Without the optional NUMBER, the longest match is taken, but
          if NUMBER is given, anything up to the NUMBERth match is
          moved.  If the NUMBER is negative, the NUMBERth longest match
          is moved. For example, if PREFIX contains the string `a=b=c',
          then compset -P '*\=' will move the string `a=b=' into the
          IPREFIX parameter, but compset -P 1 '*\=' will move only the
          string `a='.

    -s NUMBER
          As -p, but transfer the last NUMBER characters from the value
          of SUFFIX to the front of the value of ISUFFIX.

    -S [ NUMBER ] PATTERN
          As -P, but match the last portion of SUFFIX and transfer the
          matched portion to the front of the value of ISUFFIX.

    -n BEGIN [ END ]
          If the current word position as specified by the parameter
          CURRENT is greater than or equal to BEGIN, anything up to the
          BEGINth word is removed from the words array and the value of
          the parameter CURRENT is decremented by BEGIN.

          If the optional END is given, the modification is done only if
          the current word position is also less than or equal to END.
          In this case, the words from position END onwards are also
          removed from the words array.

          Both BEGIN and END may be negative to count backwards from
          the last element of the words array.

    -N BEG-PAT [ END-PAT ]
          If one of the elements of the words array before the one at
          the index given by the value of the parameter CURRENT matches
          the pattern BEG-PAT, all elements up to and including the
          matching one are removed from the words array and the value
          of CURRENT is changed to point to the same word in the
          changed array.

          If the optional pattern END-PAT is also given, and there is an
          element in the words array matching this pattern, the
          parameters are modified only if the index of this word is
          higher than the one given by the CURRENT parameter (so that
          the matching word has to be after the cursor). In this case,
          the words starting with the one matching end-pat are also
          removed from the words array. If words contains no word
          matching END-PAT, the testing and modification is performed
          as if it were not given.

    -q
          The word currently being completed is split on spaces into
          separate words, respecting the usual shell quoting
          conventions.  The resulting words are stored in the words
          array, and CURRENT, PREFIX, SUFFIX, QIPREFIX, and QISUFFIX
          are modified to reflect the word part that is completed.


     In all the above cases the return status is zero if the test
     succeeded and the parameters were modified and non-zero otherwise.
     This allows one to use this builtin in tests such as:


          if compset -P '*\='; then ...

     This forces anything up to and including the last equal sign to be
     ignored by the completion code.

compcall [ -TD ]
     This allows the use of completions defined with the compctl builtin
     from within completion widgets.  The list of matches will be
     generated as if one of the non-widget completion functions
     (complete-word, etc.)  had been called, except that only compctls
     given for specific commands are used. To force the code to try
     completions defined with the -T option of compctl and/or the
     default completion (whether defined by compctl -D or the builtin
     default) in the appropriate places, the -T and/or -D flags can be
     passed to compcall.

     The return status can be used to test if a matching compctl
     definition was found. It is non-zero if a compctl was found and
     zero otherwise.

     Note that this builtin is defined by the zsh/compctl module.



File: zsh.info,  Node: Completion Condition Codes,  Next: Completion Matching Control,  Prev: Completion Builtin Commands,  Up: Completion Widgets

19.4 Completion Condition Codes
===============================



The following additional condition codes for use within the [[ ... ]]
construct are available in completion widgets.  These work on the
special parameters.  All of these tests can also be performed by the
compset builtin, but in the case of the condition codes the contents of
the special parameters are not modified.


-prefix [ NUMBER ] PATTERN
     true if the test for the -P option of compset would succeed.

-suffix [ NUMBER ] PATTERN
     true if the test for the -S option of compset would succeed.

-after BEG-PAT
     true if the test of the -N option with only the BEG-PAT given
     would succeed.

-between BEG-PAT END-PAT
     true if the test for the -N option with both patterns would
     succeed.



File: zsh.info,  Node: Completion Matching Control,  Next: Completion Widget Example,  Prev: Completion Condition Codes,  Up: Completion Widgets

19.5 Completion Matching Control
================================

It is possible by use of the -M option of the compadd builtin command
to specify how the characters in the string to be completed (referred
to here as the command line) map onto the characters in the list of
matches produced by the completion code (referred to here as the trial
completions). Note that this is not used if the command line contains a
glob pattern and the GLOB_COMPLETE option is set or the pattern_match
of the compstate special association is set to a non-empty string.

The MATCH-SPEC given as the argument to the -M option (see *note
Completion Builtin Commands::) consists of one or more matching
descriptions separated by whitespace.  Each description consists of a
letter followed by a colon and then the patterns describing which
character sequences on the line match which character sequences in the
trial completion.  Any sequence of characters not handled in this
fashion must match exactly, as usual.

The forms of MATCH-SPEC understood are as follows. In each case, the
form with an upper case initial character retains the string already
typed on the command line as the final result of completion, while with
a lower case initial character the string on the command line is changed
into the corresponding part of the trial completion.


m:LPAT=TPAT
M:LPAT=TPAT
     Here, LPAT is a pattern that matches on the command line,
     corresponding to TPAT which matches in the trial completion.

l:LANCHOR|LPAT=TPAT
L:LANCHOR|LPAT=TPAT
l:LANCHOR||RANCHOR=TPAT
L:LANCHOR||RANCHOR=TPAT
b:LPAT=TPAT
B:LPAT=TPAT
     These letters are for patterns that are anchored by another
     pattern on the left side. Matching for LPAT and TPAT is as for m
     and M, but the pattern LPAT matched on the command line must be
     preceded by the pattern LANCHOR.  The LANCHOR can be blank to
     anchor the match to the start of the command line string;
     otherwise the anchor can occur anywhere, but must match in both
     the command line and trial completion strings.

     If no LPAT is given but a RANCHOR is, this matches the gap between
     substrings matched by LANCHOR and RANCHOR. Unlike LANCHOR, the
     RANCHOR only needs to match the trial completion string.

     The b and B forms are similar to l and L with an empty anchor, but
     need to match only the beginning of the trial completion or the
     word on the command line, respectively.

r:LPAT|RANCHOR=TPAT
R:LPAT|RANCHOR=TPAT
r:LANCHOR||RANCHOR=TPAT
R:LANCHOR||RANCHOR=TPAT
e:LPAT=TPAT
E:LPAT=TPAT
     As l, L, b and B, with the difference that the command line and
     trial completion patterns are anchored on the right side.  Here an
     empty RANCHOR and the e and E forms force the match to the end of
     the trial completion or command line string.


Each LPAT, TPAT or ANCHOR is either an empty string or consists of a
sequence of literal characters (which may be quoted with a backslash),
question marks, character classes, and correspondence classes; ordinary
shell patterns are not used.  Literal characters match only themselves,
question marks match any character, and character classes are formed as
for globbing and match any character in the given set.

Correspondence classes are defined like character classes, but with two
differences: they are delimited by a pair of braces, and negated classes
are not allowed, so the characters ! and ^ have no special meaning
directly after the opening brace.  They indicate that a range of
characters on the line match a range of characters in the trial
completion, but (unlike ordinary character classes) paired according to
the corresponding position in the sequence.  For example, to make any
ASCII lower case letter on the line match the corresponding upper case
letter in the trial completion, you can use `m:{a-z}={A-Z}' (however,
see below for the recommended form for this).  More than one pair of
classes can occur, in which case the first class before the =
corresponds to the first after it, and so on.  If one side has more
such classes than the other side, the superfluous classes behave like
normal character classes.  In anchor patterns correspondence classes
also behave like normal character classes.

The standard `[:NAME:]' forms described for standard shell patterns,
*note Filename Generation::, may appear in correspondence classes as
well as normal character classes.  The only special behaviour in
correspondence classes is if the form on the left and the form on the
right are each one of [:upper:], [:lower:].  In these cases the
character in the word and the character on the line must be the same up
to a difference in case.  Hence to make any lower case character on the
line match the corresponding upper case character in the trial
completion you can use `m:{[:lower:]}={[:upper:]}'.  Although the
matching system does not yet handle multibyte characters, this is likely
to be a future extension, at which point this syntax will handle
arbitrary alphabets; hence this form, rather than the use of explicit
ranges, is the recommended form.  In other cases `[:NAME:]' forms are
allowed.  If the two forms on the left and right are the same, the
characters must match exactly.  In remaining cases, the corresponding
tests are applied to both characters, but they are not otherwise
constrained; any matching character in one set goes with any matching
character in the other set:  this is equivalent to the behaviour of
ordinary character classes.

The pattern TPAT may also be one or two stars, `*' or `**'. This means
that the pattern on the command line can match any number of characters
in the trial completion. In this case the pattern must be anchored (on
either side); in the case of a single star, the ANCHOR then determines
how much of the trial completion is to be included -- only the
characters up to the next appearance of the anchor will be matched.
With two stars, substrings matched by the anchor can be matched, too.

Examples:

The keys of the options association defined by the parameter module are
the option names in all-lower-case form, without underscores, and
without the optional no at the beginning even though the builtins
setopt and unsetopt understand option names with upper case letters,
underscores, and the optional no.  The following alters the matching
rules so that the prefix no and any underscore are ignored when trying
to match the trial completions generated and upper case letters on the
line match the corresponding lower case letters in the words:


     compadd -M 'L:|[nN][oO]= M:_= M:{[:upper:]}={[:lower:]}' - \
       ${(k)options}

The first part says that the pattern `[nN][oO]' at the beginning (the
empty anchor before the pipe symbol) of the string on the line matches
the empty string in the list of words generated by completion, so it
will be ignored if present. The second part does the same for an
underscore anywhere in the command line string, and the third part uses
correspondence classes so that any upper case letter on the line
matches the corresponding lower case letter in the word. The use of the
upper case forms of the specification characters (L and M) guarantees
that what has already been typed on the command line (in particular the
prefix no) will not be deleted.

Note that the use of L in the first part means that it matches only
when at the beginning of both the command line string and the trial
completion. I.e., the string `_NO_f' would not be completed to
`_NO_foo', nor would `NONO_f' be completed to `NONO_foo' because of the
leading underscore or the second `NO' on the line which makes the
pattern fail even though they are otherwise ignored. To fix this, one
would use `B:[nN][oO]=' instead of the first part. As described above,
this matches at the beginning of the trial completion, independent of
other characters or substrings at the beginning of the command line
word which are ignored by the same or other MATCH-SPECs.

The second example makes completion case insensitive.  This is just the
same as in the option example, except here we wish to retain the
characters in the list of completions:


     compadd -M 'm:{[:lower:]}={[:upper:]}' ...

This makes lower case letters match their upper case counterparts.  To
make upper case letters match the lower case forms as well:


     compadd -M 'm:{[:lower:][:upper:]}={[:upper:][:lower:]}' ...

A nice example for the use of * patterns is partial word completion.
Sometimes you would like to make strings like `c.s.u' complete to
strings like `comp.source.unix', i.e. the word on the command line
consists of multiple parts, separated by a dot in this example, where
each part should be completed separately -- note, however, that the
case where each part of the word, i.e. `comp', `source' and `unix' in
this example, is to be completed from separate sets of matches is a
different problem to be solved by the implementation of the completion
widget.  The example can be handled by:


     compadd -M 'r:|.=* r:|=*' \
       - comp.sources.unix comp.sources.misc ...

The first specification says that LPAT is the empty string, while
ANCHOR is a dot; TPAT is *, so this can match anything except for the
`.' from the anchor in the trial completion word.  So in `c.s.u', the
matcher sees `c', followed by the empty string, followed by the anchor
`.', and likewise for the second dot, and replaces the empty strings
before the anchors, giving `c[omp].s[ources].u[nix]', where the last
part of the completion is just as normal.

With the pattern shown above, the string `c.u' could not be completed
to `comp.sources.unix' because the single star means that no dot
(matched by the anchor) can be skipped. By using two stars as in
`r:|.=**', however, `c.u' could be completed to `comp.sources.unix'.
This also shows that in some cases, especially if the anchor is a real
pattern, like a character class, the form with two stars may result in
more matches than one would like.

The second specification is needed to make this work when the cursor is
in the middle of the string on the command line and the option
COMPLETE_IN_WORD is set. In this case the completion code would
normally try to match trial completions that end with the string as
typed so far, i.e. it will only insert new characters at the cursor
position rather than at the end.  However in our example we would like
the code to recognise matches which contain extra characters after the
string on the line (the `nix' in the example).  Hence we say that the
empty string at the end of the string on the line matches any characters
at the end of the trial completion.

More generally, the specification


     compadd -M 'r:|[.,_-]=* r:|=*' ...

allows one to complete words with abbreviations before any of the
characters in the square brackets.  For example, to complete
veryverylongfile.c rather than veryverylongheader.h with the above in
effect, you can just type very.c before attempting completion.

The specifications with both a left and a right anchor are useful to
complete partial words whose parts are not separated by some special
character. For example, in some places strings have to be completed
that are formed `LikeThis' (i.e. the separate parts are determined by a
leading upper case letter) or maybe one has to complete strings with
trailing numbers. Here one could use the simple form with only one
anchor as in:


     compadd -M 'r:|[[:upper:]0-9]=* r:|=*' LikeTHIS FooHoo 5foo123 5bar234

But with this, the string `H' would neither complete to `FooHoo' nor to
`LikeTHIS' because in each case there is an upper case letter before
the `H' and that is matched by the anchor. Likewise, a `2' would not be
completed. In both cases this could be changed by using
`r:|[[:upper:]0-9]=**', but then `H' completes to both `LikeTHIS' and
`FooHoo' and a `2' matches the other strings because characters can be
inserted before every upper case letter and digit. To avoid this one
would use:


     compadd -M 'r:[^[:upper:]0-9]||[[:upper:]0-9]=** r:|=*' \
         LikeTHIS FooHoo foo123 bar234

By using these two anchors, a `H' matches only upper case `H's that are
immediately preceded by something matching the left anchor
`[^[:upper:]0-9]'. The effect is, of course, that `H' matches only the
string `FooHoo', a `2' matches only `bar234' and so on.

When using the completion system (see *note Completion System::), users
can define match specifications that are to be used for specific
contexts by using the matcher and matcher-list styles. The values for
the latter will be used everywhere.



File: zsh.info,  Node: Completion Widget Example,  Prev: Completion Matching Control,  Up: Completion Widgets

19.6 Completion Widget Example
==============================



The first step is to define the widget:


     zle -C complete complete-word complete-files

Then the widget can be bound to a key using the bindkey builtin command:


     bindkey '^X\t' complete

After that the shell function complete-files will be invoked after
typing control-X and TAB. The function should then generate the
matches, e.g.:


     complete-files () { compadd - * }

This function will complete files in the current directory matching the
current word.

File: zsh.info,  Node: Completion System,  Next: Completion Using compctl,  Prev: Completion Widgets,  Up: Top

20 Completion System
********************



20.1 Description
================

This describes the shell code for the `new' completion system, referred
to as compsys.  It is written in shell functions based on the features
described in the previous chapter, *note Completion Widgets::.

The features are contextual, sensitive to the point at which completion
is started.  Many completions are already provided.  For this reason, a
user can perform a great many tasks without knowing any details beyond
how to initialize the system, which is described in *note
Initialization::.

The context that decides what completion is to be performed may be
   * an argument or option position: these describe the position on the
     command line at which completion is requested.  For example `first
     argument to rmdir, the word being completed names a directory';

   * a special context, denoting an element in the shell's syntax.  For
     example `a word in command position' or `an array subscript'.


A full context specification contains other elements, as we shall
describe.

Besides commands names and contexts, the system employs two more
concepts, _styles_ and _tags_.  These provide ways for the user to
configure the system's behaviour.

Tags play a dual role.  They serve as a classification system for the
matches, typically indicating a class of object that the user may need
to distinguish.  For example, when completing arguments of the ls
command the user may prefer to try files before directories, so both of
these are tags.  They also appear as the rightmost element in a context
specification.

Styles modify various operations of the completion system, such as
output formatting, but also what kinds of completers are used (and in
what order), or which tags are examined.  Styles may accept arguments
and are manipulated using the zstyle command described in *note The
zsh/zutil Module::.

In summary, tags describe _what_ the completion objects are, and style
how they are to be completed.  At various points of execution, the
completion system checks what styles and/or tags are defined for the
current context, and uses that to modify its behavior.  The full
description of context handling, which determines how tags and other
elements of the context influence the behaviour of styles, is described
in *note Completion System Configuration::.

When a completion is requested, a dispatcher function is called; see
the description of _main_complete in the list of control functions
below. This dispatcher decides which function should be called to
produce the completions, and calls it. The result is passed to one or
more _completers_, functions that implement individual completion
strategies: simple completion, error correction, completion with error
correction, menu selection, etc.

More generally, the shell functions contained in the completion system
are of two types:
   * those beginning `comp' are to be called directly; there are only a
     few of these;

   * those beginning `_' are called by the completion code.  The shell
     functions of this set, which implement completion behaviour and
     may be bound to keystrokes, are referred to as `widgets'.  These
     proliferate as new completions are required.



* Menu:

* Initialization::
* Completion System Configuration::
* Control Functions::
* Bindable Commands::
* Completion Functions::
* Completion Directories::


File: zsh.info,  Node: Initialization,  Next: Completion System Configuration,  Up: Completion System

20.2 Initialization
===================



If the system was installed completely, it should be enough to call the
shell function compinit from your initialization file; see the next
section.  However, the function compinstall can be run by a user to
configure various aspects of the completion system.

Usually, compinstall will insert code into .zshrc, although if that is
not writable it will save it in another file and tell you that file's
location.  Note that it is up to you to make sure that the lines added
to .zshrc are actually run; you may, for example, need to move them to
an earlier place in the file if .zshrc usually returns early.  So long
as you keep them all together (including the comment lines at the start
and finish), you can rerun compinstall and it will correctly locate and
modify these lines.  Note, however, that any code you add to this
section by hand is likely to be lost if you rerun compinstall, although
lines using the command `zstyle' should be gracefully handled.

The new code will take effect next time you start the shell, or run
.zshrc by hand; there is also an option to make them take effect
immediately.  However, if compinstall has removed definitions, you will
need to restart the shell to see the changes.

To run compinstall you will need to make sure it is in a directory
mentioned in your fpath parameter, which should already be the case if
zsh was properly configured as long as your startup files do not remove
the appropriate directories from fpath.  Then it must be autoloaded
(`autoload -U compinstall' is recommended).  You can abort the
installation any time you are being prompted for information, and your
.zshrc will not be altered at all; changes only take place right at the
end, where you are specifically asked for confirmation.



20.2.1 Use of compinit
----------------------



This section describes the use of compinit to initialize completion for
the current session when called directly; if you have run compinstall
it will be called automatically from your .zshrc.

To initialize the system, the function compinit should be in a
directory mentioned in the fpath parameter, and should be autoloaded
(`autoload -U compinit' is recommended), and then run simply as
`compinit'.  This will define a few utility functions, arrange for all
the necessary shell functions to be autoloaded, and will then re-define
all widgets that do completion to use the new system.  If you use the
menu-select widget, which is part of the zsh/complist module, you
should make sure that that module is loaded before the call to compinit
so that that widget is also re-defined.  If completion styles (see
below) are set up to perform expansion as well as completion by
default, and the TAB key is bound to expand-or-complete, compinit will
rebind it to complete-word; this is necessary to use the correct form
of expansion.

Should you need to use the original completion commands, you can still
bind keys to the old widgets by putting a `.' in front of the widget
name, e.g. `.expand-or-complete'.

To speed up the running of compinit, it can be made to produce a dumped
configuration that will be read in on future invocations; this is the
default, but can be turned off by calling compinit with the option -D.
The dumped file is .zcompdump in the same directory as the startup
files (i.e. $ZDOTDIR or $HOME); alternatively, an explicit file name
can be given by `compinit -d DUMPFILE'.  The next invocation of
compinit will read the dumped file instead of performing a full
initialization.

If the number of completion files changes, compinit will recognise this
and produce a new dump file.  However, if the name of a function or the
arguments in the first line of a #compdef function (as described below)
change, it is easiest to delete the dump file by hand so that compinit
will re-create it the next time it is run.  The check performed to see
if there are new functions can be omitted by giving the option -C.  In
this case the dump file will only be created if there isn't one already.

The dumping is actually done by another function, compdump, but you
will only need to run this yourself if you change the configuration
(e.g. using compdef) and then want to dump the new one.  The name of
the old dumped file will be remembered for this purpose.

If the parameter _compdir is set, compinit uses it as a directory where
completion functions can be found; this is only necessary if they are
not already in the function search path.

For security reasons compinit also checks if the completion system
would use files not owned by root or by the current user, or files in
directories that are world- or group-writable or that are not owned by
root or by the current user.  If such files or directories are found,
compinit will ask if the completion system should really be used.  To
avoid these tests and make all files found be used without asking, use
the option -u, and to make compinit silently ignore all insecure files
and directories use the option -i.  This security check is skipped
entirely when the -C option is given.

The security check can be retried at any time by running the function
compaudit.  This is the same check used by compinit, but when it is
executed directly any changes to fpath are made local to the function
so they do not persist.  The directories to be checked may be passed as
arguments; if none are given, compaudit uses fpath and _compdir to find
completion system directories, adding missing ones to fpath as
necessary.  To force a check of exactly the directories currently named
in fpath, set _compdir to an empty string before calling compaudit or
compinit.

The function bashcompinit provides compatibility with bash's
programmable completion system.  When run it will define the functions,
compgen and complete which correspond to the bash builtins with the
same names.  It will then be possible to use completion specifications
and functions written for bash.



20.2.2 Autoloaded files
-----------------------



The convention for autoloaded functions used in completion is that they
start with an underscore; as already mentioned, the fpath/FPATH
parameter must contain the directory in which they are stored.  If zsh
was properly installed on your system, then fpath/FPATH automatically
contains the required directories for the standard functions.

For incomplete installations, if compinit does not find enough files
beginning with an underscore (fewer than twenty) in the search path, it
will try to find more by adding the directory _compdir to the search
path.  If that directory has a subdirectory named Base, all
subdirectories will be added to the path.  Furthermore, if the
subdirectory Base has a subdirectory named Core, compinit will add all
subdirectories of the subdirectories is to the path: this allows the
functions to be in the same format as in the zsh source distribution.

When compinit is run, it searches all such files accessible via
fpath/FPATH and reads the first line of each of them.  This line should
contain one of the tags described below.  Files whose first line does
not start with one of these tags are not considered to be part of the
completion system and will not be treated specially.

The tags are:


#compdef NAMES... [ -[pP] PATTERNS... [ -N NAMES... ] ]
     The file will be made autoloadable and the function defined in it
     will be called when completing NAMES, each of which is either the
     name of a command whose arguments are to be completed or one of a
     number of special contexts in the form -CONTEXT- described below.

     Each NAME may also be of the form `CMD=SERVICE'.  When completing
     the command CMD, the function typically behaves as if the command
     (or special context) SERVICE was being completed instead.  This
     provides a way of altering the behaviour of functions that can
     perform many different completions.  It is implemented by setting
     the parameter $service when calling the function; the function may
     choose to interpret this how it wishes, and simpler functions will
     probably ignore it.

     If the #compdef line contains one of the options -p or -P, the
     words following are taken to be patterns.  The function will be
     called when completion is attempted for a command or context that
     matches one of the patterns.  The options -p and -P are used to
     specify patterns to be tried before or after other completions
     respectively.  Hence -P may be used to specify default actions.

     The option -N is used after a list following -p or -P; it
     specifies that remaining words no longer define patterns.  It is
     possible to toggle between the three options as many times as
     necessary.

#compdef -k STYLE KEY-SEQUENCES...
     This option creates a widget behaving like the builtin widget
     STYLE and binds it to the given KEY-SEQUENCES, if any.  The STYLE
     must be one of the builtin widgets that perform completion, namely
     complete-word, delete-char-or-list, expand-or-complete,
     expand-or-complete-prefix, list-choices, menu-complete,
     menu-expand-or-complete, or reverse-menu-complete.  If the
     zsh/complist module is loaded (see *note The zsh/complist
     Module::) the widget menu-select is also available.

     When one of the KEY-SEQUENCES is typed, the function in the file
     will be invoked to generate the matches.  Note that a key will not
     be re-bound if it already was (that is, was bound to something
     other than undefined-key).  The widget created has the same name
     as the file and can be bound to any other keys using bindkey as
     usual.

#compdef -K WIDGET-NAME STYLE KEY-SEQUENCES ...
     This is similar to -k except that only one KEY-SEQUENCES argument
     may be given for each WIDGET-NAME STYLE pair.  However, the entire
     set of three arguments may be repeated with a different set of
     arguments.  Note in particular that the WIDGET-NAME must be
     distinct in each set.  If it does not begin with `_' this will be
     added.  The WIDGET-NAME should not clash with the name of any
     existing widget: names based on the name of the function are most
     useful.  For example,


          #compdef -K _foo_complete complete-word "^X^C" \
            _foo_list list-choices "^X^D"

     (all on one line) defines a widget _foo_complete for completion,
     bound to `^X^C', and a widget _foo_list for listing, bound to
     `^X^D'.

#autoload [ OPTIONS ]
     Functions with the #autoload tag are marked for autoloading but
     are not otherwise treated specially.  Typically they are to be
     called from within one of the completion functions.  Any OPTIONS
     supplied will be passed to the autoload builtin; a typical use is
     +X to force the function to be loaded immediately.  Note that the
     -U and -z flags are always added implicitly.


The # is part of the tag name and no white space is allowed after it.
The #compdef tags use the compdef function described below; the main
difference is that the name of the function is supplied implicitly.

The special contexts for which completion functions can be defined are:


-array-value-
     The right hand side of an array-assignment (`foo=(...)')

-brace-parameter-
     The name of a parameter expansion within braces (`${...}')

-assign-parameter-
     The name of a parameter in an assignment, i.e. on the left hand
     side of an `='

-command-
     A word in command position

-condition-
     A word inside a condition (`[[...]]')

-default-
     Any word for which no other completion is defined

-equal-
     A word beginning with an equals sign

-first-
     This is tried before any other completion function.  The function
     called may set the _compskip parameter to one of various values:
     all: no further completion is attempted; a string containing the
     substring patterns: no pattern completion functions will be
     called; a string containing default: the function for the
     `-default-' context will not be called, but functions defined for
     commands will

-math-
     Inside mathematical contexts, such as `((...))'

-parameter-
     The name of a parameter expansion (`$...')

-redirect-
     The word after a redirection operator.

-subscript-
     The contents of a parameter subscript.

-tilde-
     After an initial tilde (`~'), but before the first slash in the
     word.

-value-
     On the right hand side of an assignment.


Default implementations are supplied for each of these contexts.  In
most cases the context -CONTEXT- is implemented by a corresponding
function _CONTEXT, for example the context `-tilde-' and the function
`_tilde').

The contexts -redirect- and -value- allow extra context-specific
information.  (Internally, this is handled by the functions for each
context calling the function _dispatch.)  The extra information is
added separated by commas.

For the -redirect- context, the extra information is in the form
`-redirect-,OP,COMMAND', where OP is the redirection operator and
COMMAND is the name of the command on the line.  If there is no command
on the line yet, the COMMAND field will be empty.

For the -value- context, the form is `-value-,NAME,COMMAND', where NAME
is the name of the parameter.  In the case of elements of an
associative array, for example `assoc=(key <TAB>', NAME is expanded to
`NAME-KEY'.  In certain special contexts, such as completing after
`make CFLAGS=', the COMMAND part gives the name of the command, here
make; otherwise it is empty.

It is not necessary to define fully specific completions as the
functions provided will try to generate completions by progressively
replacing the elements with `-default-'.  For example, when completing
after `foo=<TAB>', _value will try the names `-value-,foo,' (note the
empty COMMAND part), `-value-,foo,-default-'
and`-value-,-default-,-default-', in that order, until it finds a
function to handle the context.

As an example:


     compdef '_files -g "*.log"' '-redirect-,2>,-default-'

completes files matching `*.log' after `2> <TAB>' for any command with
no more specific handler defined.

Also:


     compdef _foo -value-,-default-,-default-

specifies that _foo provides completions for the values of parameters
for which no special function has been defined.  This is usually
handled by the function _value itself.

The same lookup rules are used when looking up styles (as described
below); for example


     zstyle ':completion:*:*:-redirect-,2>,*:*' file-patterns '*.log'

is another way to make completion after `2> <TAB>' complete files
matching `*.log'.



20.2.3 Functions
----------------

The following function is defined by compinit and may be called
directly.


compdef [ -an ] FUNCTION NAMES... [ -[pP] PATTERNS... [ -N NAMES... ] ]
compdef -d NAMES...
compdef -k [ -an ] FUNCTION STYLE KEY-SEQUENCES...
compdef -K [ -an ] FUNCTION NAME STYLE KEY-SEQUENCES ...
     The first form defines the FUNCTION to call for completion in the
     given contexts as described for the #compdef tag above.

     Alternatively, all the arguments may have the form `CMD=SERVICE'.
     Here SERVICE should already have been defined by `CMD1=SERVICE'
     lines in #compdef files, as described above.  The argument for CMD
     will be completed in the same way as SERVICE.

     The FUNCTION argument may alternatively be a string containing any
     shell code.  The string will be executed using the eval builtin
     command to generate completions.  This provides a way of avoiding
     having to define a new completion function.  For example, to
     complete files ending in `.h' as arguments to the command foo:


          compdef '_files -g "*.h"' foo

     The option -n prevents any completions already defined for the
     command or context from being overwritten.

     The option -d deletes any completion defined for the command or
     contexts listed.

     The NAMES may also contain -p, -P and -N options as described for
     the #compdef tag.  The effect on the argument list is identical,
     switching between definitions of patterns tried initially,
     patterns tried finally, and normal commands and contexts.

     The parameter $_compskip may be set by any function defined for a
     pattern context.  If it is set to a value containing the substring
     `patterns' none of the pattern-functions will be called; if it is
     set to a value containing the substring `all', no other function
     will be called.

     The form with -k defines a widget with the same name as the
     FUNCTION that will be called for each of the KEY-SEQUENCES; this
     is like the #compdef -k tag.  The function should generate the
     completions needed and will otherwise behave like the builtin
     widget whose name is given as the STYLE argument.  The widgets
     usable for this are: complete-word, delete-char-or-list,
     expand-or-complete, expand-or-complete-prefix, list-choices,
     menu-complete, menu-expand-or-complete, and reverse-menu-complete,
     as well as menu-select if the zsh/complist module is loaded.  The
     option -n prevents the key being bound if it is already to bound
     to something other than undefined-key.

     The form with -K is similar and defines multiple widgets based on
     the same FUNCTION, each of which requires the set of three
     arguments NAME, STYLE and KEY-SEQUENCES, where the latter two are
     as for -k and the first must be a unique widget name beginning
     with an underscore.

     Wherever applicable, the -a option makes the FUNCTION
     autoloadable, equivalent to autoload -U FUNCTION.


The function compdef can be used to associate existing completion
functions with new commands.  For example,


     compdef _pids foo

uses the function _pids to complete process IDs for the command foo.

Note also the _gnu_generic function described below, which can be used
to complete options for commands that understand the `--help' option.



File: zsh.info,  Node: Completion System Configuration,  Next: Control Functions,  Prev: Initialization,  Up: Completion System

20.3 Completion System Configuration
====================================



This section gives a short overview of how the completion system works,
and then more detail on how users can configure how and when matches are
generated.



20.3.1 Overview
---------------

When completion is attempted somewhere on the command line the
completion system first works out the context.  This takes account of a
number of things including the command word (such as `grep' or `zsh')
and options to which the current word may be an argument (such as the
`-o' option to zsh which takes a shell option as an argument).

This context information is condensed into a string consisting of
multiple fields separated by colons, referred to simply as `the context'
in the remainder of the documentation.  This is used to look up
_styles_, context-sensitive options that can be used to configure the
completion system.  The context used for lookup may vary during the same
call to the completion system.

The context string always consists of a fixed set of fields, separated
by colons and with a leading colon before the first, in the form
:completion:FUNCTION:COMPLETER:COMMAND:ARGUMENT:tag.  These have the
following meaning:


   * The literal string completion, saying that this style is used by
     the completion system.  This distinguishes the context from those
     used by, for example, zle widgets and ZFTP functions.

   * The FUNCTION, if completion is called from a named widget rather
     than through the normal completion system.  Typically this is
     blank, but it is set by special widgets such as predict-on and the
     various functions in the Widget directory of the distribution to
     the name of that function, often in an abbreviated form.

   * The COMPLETER currently active, the name of the function without
     the leading underscore and with other underscores converted to
     hyphens.  A `completer' is in overall control of how completion is
     to be performed; `complete' is the simplest, but other completers
     exist to perform related tasks such as correction, or to modify
     the behaviour of a later completer.  See *note Control Functions::
     for more information.

   * The COMMAND or a special -CONTEXT-, just at it appears following
     the #compdef tag or the compdef function.  Completion functions
     for commands that have sub-commands usually modify this field to
     contain the name of the command followed by a minus sign and the
     sub-command.  For example, the completion function for the cvs
     command sets this field to cvs-add when completing arguments to
     the add subcommand.

   * The ARGUMENT; this indicates which command line or option argument
     we are completing.  For command arguments this generally takes the
     form argument-N, where N is the number of the argument, and for
     arguments to options the form option-OPT-N where N is the number
     of the argument to option OPT.  However, this is only the case if
     the command line is parsed with standard UNIX-style options and
     arguments, so many completions do not set this.

   * The TAG.  As described previously, tags are used to discriminate
     between the types of matches a completion function can generate in
     a certain context.  Any completion function may use any tag name
     it likes, but a list of the more common ones is given below.


The context is gradually put together as the functions are executed,
starting with the main entry point, which adds :completion: and the
FUNCTION element if necessary.  The completer then adds the COMPLETER
element.  The contextual completion adds the COMMAND and ARGUMENT
options.  Finally, the TAG is added when the types of completion are
known.  For example, the context name


     :completion::complete:dvips:option-o-1:files

says that normal completion was attempted as the first argument to the
option -o of the command dvips:


     dvips -o ...

and the completion function will generate filenames.

Usually completion will be tried for all possible tags in an order given
by the completion function.  However, this can be altered by using the
tag-order style.  Completion is then restricted to the list of given
tags in the given order.

The _complete_help bindable command shows all the contexts and tags
available for completion at a particular point.  This provides an easy
way of finding information for tag-order and other styles.  It is
described in *note Bindable Commands::.

Styles determine such things as how the matches are generated, similarly
to shell options but with much more control.  They can have any number
of strings as their value.  They are defined with the zstyle builtin
command (*note The zsh/zutil Module::).

When looking up styles the completion system uses full context names,
including the tag.  Looking up the value of a style therefore consists
of two things:  the context, which may be matched as a pattern, and the
name of the style itself, which must be given exactly.

For example, many completion functions can generate matches in a simple
and a verbose form and use the verbose style to decide which form
should be used.  To make all such functions use the verbose form, put


     zstyle ':completion:*' verbose yes

in a startup file (probably .zshrc).  This gives the verbose style the
value yes in every context inside the completion system, unless that
context has a more specific definition.  It is best to avoid giving the
context as `*' in case the style has some meaning outside the
completion system.

Many such general purpose styles can be configured simply by using the
compinstall function.

A more specific example of the use of the verbose style is by the
completion for the kill builtin.  If the style is set, the builtin
lists full job texts and process command lines; otherwise it shows the
bare job numbers and PIDs.  To turn the style off for this use only:


     zstyle ':completion:*:*:kill:*' verbose no

For even more control, the style can use one of the tags `jobs' or
`processes'.  To turn off verbose display only for jobs:


     zstyle ':completion:*:*:kill:*:jobs' verbose no

The -e option to zstyle even allows completion function code to appear
as the argument to a style; this requires some understanding of the
internals of completion functions (see *note Completion Widgets::)).
For example,


     zstyle -e ':completion:*' hosts 'reply=($myhosts)'

This forces the value of the hosts style to be read from the variable
myhosts each time a host name is needed; this is useful if the value of
myhosts can change dynamically.  For another useful example, see the
example in the description of the file-list style below.  This form can
be slow and should be avoided for commonly examined styles such as menu
and list-rows-first.

Note that the order in which styles are _defined_ does not matter; the
style mechanism uses the most specific possible match for a particular
style to determine the set of values.  More precisely, strings are
preferred over patterns (for example, `:completion::complete:foo' is
more specific than `:completion::complete:*'), and longer patterns are
preferred over shorter patterns.

Style names like those of tags are arbitrary and depend on the
completion function.  However, the following two sections list some of
the most common tags and styles.



20.3.2 Standard Tags
--------------------



Some of the following are only used when looking up particular styles
and do not refer to a type of match.


accounts
     used to look up the users-hosts style

all-expansions
     used by the _expand completer when adding the single string
     containing all possible expansions

all-files
     for the names of all files (as distinct from a particular subset,
     see the globbed-files tag).

arguments
     for arguments to a command

arrays
     for names of array parameters

association-keys
     for keys of associative arrays; used when completing inside a
     subscript to a parameter of this type

bookmarks
     when completing bookmarks (e.g. for URLs and the zftp function
     suite)

builtins
     for names of builtin commands

characters
     for single characters in arguments of commands such as stty.
     Also used when completing character classes after an opening
     bracket

colormapids
     for X colormap ids

colors
     for color names

commands
     for names of external commands.  Also used by complex commands
     such as cvs when completing names subcommands.

contexts
     for contexts in arguments to the zstyle builtin command

corrections
     used by the _approximate and _correct completers for possible
     corrections

cursors
     for cursor names used by X programs

default
     used in some contexts to provide a way of supplying a default when
     more specific tags are also valid.  Note that this tag is used
     when only the FUNCTION field of the context name is set

descriptions
     used when looking up the value of the format style to generate
     descriptions for types of matches

devices
     for names of device special files

directories
     for names of directories

directory-stack
     for entries in the directory stack

displays
     for X display names

domains
     for network domains

expansions
     used by the _expand completer for individual words (as opposed to
     the complete set of expansions) resulting from the expansion of a
     word on the command line

extensions
     for X server extensions

file-descriptors
     for numbers of open file descriptors

files
     the generic file-matching tag used by functions completing
     filenames

fonts
     for X font names

fstypes
     for file system types (e.g. for the mount command)

functions
     names of functions -- normally shell functions, although certain
     commands may understand other kinds of function

globbed-files
     for filenames when the name has been generated by pattern matching

groups
     for names of user groups

history-words
     for words from the history

hosts
     for hostnames

indexes
     for array indexes

jobs
     for jobs (as listed by the `jobs' builtin)

interfaces
     for network interfaces

keymaps
     for names of zsh keymaps

keysyms
     for names of X keysyms

libraries
     for names of system libraries

limits
     for system limits

local-directories
     for names of directories that are subdirectories of the current
     working directory when completing arguments of cd and related
     builtin commands (compare path-directories)

manuals
     for names of manual pages

mailboxes
     for e-mail folders

maps
     for map names (e.g. NIS maps)

messages
     used to look up the format style for messages

modifiers
     for names of X modifiers

modules
     for modules (e.g. zsh modules)

my-accounts
     used to look up the users-hosts style

named-directories
     for named directories (you wouldn't have guessed that, would you?)

names
     for all kinds of names

newsgroups
     for USENET groups

nicknames
     for nicknames of NIS maps

options
     for command options

original
     used by the _approximate, _correct and _expand completers when
     offering the original string as a match

other-accounts
     used to look up the users-hosts style

other-files
     for the names of any non-directory files.  This is used instead of
     all-files when the list-dirs-first style is in effect.

packages
     for packages (e.g. rpm or installed Debian packages)

parameters
     for names of parameters

path-directories
     for names of directories found by searching the cdpath array when
     completing arguments of cd and related builtin commands (compare
     local-directories)

paths
     used to look up the values of the expand, ambiguous and
     special-dirs styles

pods
     for perl pods (documentation files)

ports
     for communication ports

prefixes
     for prefixes (like those of a URL)

printers
     for print queue names

processes
     for process identifiers

processes-names
     used to look up the command style when generating the names of
     processes for killall

sequences
     for sequences (e.g. mh sequences)

sessions
     for sessions in the zftp function suite

signals
     for signal names

strings
     for strings (e.g. the replacement strings for the cd builtin
     command)

styles
     for styles used by the zstyle builtin command

suffixes
     for filename extensions

tags
     for tags (e.g. rpm tags)

targets
     for makefile targets

time-zones
     for time zones (e.g. when setting the TZ parameter)

types
     for types of whatever (e.g. address types for the xhost command)

urls
     used to look up the urls and local styles when completing URLs

users
     for usernames

values
     for one of a set of values in certain lists

variant
     used by _pick_variant to look up the command to run when
     determining what program is installed for a particular command
     name.

visuals
     for X visuals

warnings
     used to look up the format style for warnings

widgets
     for zsh widget names

windows
     for IDs of X windows

zsh-options
     for shell options



20.3.3 Standard Styles
----------------------



Note that the values of several of these styles represent boolean
values.  Any of the strings `true', `on', `yes', and `1' can be used
for the value `true' and any of the strings `false', `off', `no', and
`0' for the value `false'.  The behavior for any other value is
undefined except where explicitly mentioned.  The default value may be
either true or false if the style is not set.

Some of these styles are tested first for every possible tag
corresponding to a type of match, and if no style was found, for the
default tag.  The most notable styles of this type are menu,
list-colors and styles controlling completion listing such as
list-packed and last-prompt).  When tested for the default tag, only
the FUNCTION field of the context will be set so that a style using the
default tag will normally be defined along the lines of:


     zstyle ':completion:*:default' menu ...


accept-exact
     This is tested for the default tag in addition to the tags valid
     for the current context.  If it is set to `true' and any of the
     trial matches is the same as the string on the command line, this
     match will immediately be accepted (even if it would otherwise be
     considered ambiguous).

     When completing pathnames (where the tag used is `paths') this
     style accepts any number of patterns as the value in addition to
     the boolean values.  Pathnames matching one of these patterns will
     be accepted immediately even if the command line contains some
     more partially typed pathname components and these match no file
     under the directory accepted.

     This style is also used by the _expand completer to decide if
     words beginning with a tilde or parameter expansion should be
     expanded.  For example, if there are parameters foo and foobar,
     the string `$foo' will only be expanded if accept-exact is set to
     `true'; otherwise the completion system will be allowed to
     complete $foo to $foobar. If the style is set to `continue',
     _expand will add the expansion as a match and the completion
     system will also be allowed to continue.

accept-exact-dirs
     This is used by filename completion.  Unlike accept-exact it is a
     boolean.  By default, filename completion examines all components
     of a path to see if there are completions of that component, even
     if the component matches an existing directory.  For example, when
     completion after /usr/bin/, the function examines possible
     completions to /usr.

     When this style is true, any prefix of a path that matches an
     existing directory is accepted without any attempt to complete it
     further.  Hence, in the given example, the path /usr/bin/ is
     accepted immediately and completion tried in that directory.

     If you wish to inhibit this behaviour entirely, set the
     path-completion style (see below) to false.

add-space
     This style is used by the _expand completer.  If it is true (the
     default), a space will be inserted after all words resulting from
     the expansion, or a slash in the case of directory names.  If the
     value is `file', the completer will only add a space to names of
     existing files.  Either a boolean true or the value `file' may be
     combined with `subst', in which case the completer will not add a
     space to words generated from the expansion of a substitution of
     the form `$(...)' or `${...}'.

     The _prefix completer uses this style as a simple boolean value to
     decide if a space should be inserted before the suffix.

ambiguous
     This applies when completing non-final components of filename
     paths, in other words those with a trailing slash.  If it is set,
     the cursor is left after the first ambiguous component, even if
     menu completion is in use.  The style is always tested with the
     paths tag.

assign-list
     When completing after an equals sign that is being treated as an
     assignment, the completion system normally completes only one
     filename.  In some cases the value  may be a list of filenames
     separated by colons, as with PATH and similar parameters.  This
     style can be set to a list of patterns matching the names of such
     parameters.

     The default is to complete lists when the word on the line already
     contains a colon.

auto-description
     If set, this style's value will be used as the description for
     options that are not described by the completion functions, but
     that have exactly one argument.  The sequence `%d' in the value
     will be replaced by the description for this argument.  Depending
     on personal preferences, it may be useful to set this style to
     something like `specify: %d'.  Note that this may not work for
     some commands.

avoid-completer
     This is used by the _all_matches completer to decide if the string
     consisting of all matches should be added to the list currently
     being generated.  Its value is a list of names of completers.  If
     any of these is the name of the completer that generated the
     matches in this completion, the string will not be added.

     The default value for this style is `_expand _old_list _correct
     _approximate', i.e. it contains the completers for which a string
     with all matches will almost never be wanted.

cache-path
     This style defines the path where any cache files containing dumped
     completion data are stored.  It defaults to
     `$ZDOTDIR/.zcompcache', or `$HOME/.zcompcache' if $ZDOTDIR is not
     defined.  The completion cache will not be used unless the
     use-cache style is set.

cache-policy
     This style defines the function that will be used to determine
     whether a cache needs rebuilding.  See the section on the
     _cache_invalid function below.

call-command
     This style is used in the function for commands such as make and
     ant where calling the command directly to generate matches suffers
     problems such as being slow or, as in the case of make can
     potentially cause actions in the makefile to be executed. If it is
     set to `true' the command is called to generate matches. The
     default value of this style is `false'.

command
     In many places, completion functions need to call external
     commands to generate the list of completions.  This style can be
     used to override the command that is called in some such cases.
     The elements of the value are joined with spaces to form a command
     line to execute.  The value can also start with a hyphen, in which
     case the usual command will be added to the end; this is most
     useful for putting `builtin' or `command' in front to make sure
     the appropriate version of a command is called, for example to
     avoid calling a shell function with the same name as an external
     command.

     As an example, the completion function for process IDs uses this
     style with the processes tag to generate the IDs to complete and
     the list of processes to display (if the verbose style is `true').
     The list produced by the command should look like the output of the
     ps command.  The first line is not displayed, but is searched for
     the string `PID' (or `pid') to find the position of the process
     IDs in the following lines.  If the line does not contain `PID',
     the first numbers in each of the other lines are taken as the
     process IDs to complete.

     Note that the completion function generally has to call the
     specified command for each attempt to generate the completion
     list.  Hence care should be taken to specify only commands that
     take a short time to run, and in particular to avoid any that may
     never terminate.

command-path
     This is a list of directories to search for commands to complete.
     The default for this style is the value of the special parameter
     path.

commands
     This is used by the function completing sub-commands for the system
     initialisation scripts (residing in /etc/init.d or somewhere not
     too far away from that).  Its values give the default commands to
     complete for those commands for which the completion function isn't
     able to find them out automatically.  The default for this style
     are the two strings `start' and `stop'.

complete
     This is used by the _expand_alias function when invoked as a
     bindable command.  If set to `true' and the word on the command
     line is not the name of an alias, matching alias names will be
     completed.

complete-options
     This is used by the completer for cd, chdir and pushd.  For these
     commands a - is used to introduce a directory stack entry and
     completion of these is far more common than completing options.
     Hence unless the value of this style is true options will not be
     completed, even after an initial -.  If it is true, options will
     be completed after an initial - unless there is a preceding -- on
     the command line.

completer
     The strings given as the value of this style provide the names of
     the completer functions to use. The available completer functions
     are described in *note Control Functions::.

     Each string may be either the name of a completer function or a
     string of the form `FUNCTION:NAME'.  In the first case the
     COMPLETER field of the context will contain the name of the
     completer without the leading underscore and with all other
     underscores replaced by hyphens.  In the second case the FUNCTION
     is the name of the completer to call, but the context will contain
     the user-defined NAME in the COMPLETER field of the context.  If
     the NAME starts with a hyphen, the string for the context will be
     build from the name of the completer function as in the first case
     with the NAME appended to it.  For example:


          zstyle ':completion:*' completer _complete _complete:-foo

     Here, completion will call the _complete completer twice, once
     using `complete' and once using `complete-foo' in the COMPLETER
     field of the context.  Normally, using the same completer more
     than once only makes sense when used with the `FUNCTIONS:NAME'
     form, because otherwise the context name will be the same in all
     calls to the completer; possible exceptions to this rule are the
     _ignored and _prefix completers.

     The default value for this style is `_complete _ignored': only
     completion will be done, first using the ignored-patterns style
     and the $fignore array and then without ignoring matches.

condition
     This style is used by the _list completer function to decide if
     insertion of matches should be delayed unconditionally. The
     default is `true'.

delimiters
     This style is used when adding a delimiter for use with history
     modifiers or glob qualifiers that have delimited arguments.  It is
     an array of preferred delimiters to add.  Non-special characters
     are preferred as the completion system may otherwise become
     confused.  The default list is :, +, /, -, %.  The list may be
     empty to force a delimiter to be typed.

disabled
     If this is set to `true', the _expand_alias completer and bindable
     command will try to expand disabled aliases, too.  The default is
     `false'.

domains
     A list of names of network domains for completion.  If this is not
     set, domain names will be taken from the file /etc/resolv.conf.

environ
     The environ style is used when completing for `sudo'.  It is set
     to an array of `VAR=VALUE' assignments to be exported into the
     local environment before the completion for the target command is
     invoked.
          zstyle :complete:sudo: environ \
            PATH="/sbin:/usr/sbin:$PATH" HOME="/root"

expand
     This style is used when completing strings consisting of multiple
     parts, such as path names.

     If one of its values is the string `prefix', the partially typed
     word from the line will be expanded as far as possible even if
     trailing parts cannot be completed.

     If one of its values is the string `suffix', matching names for
     components after the first ambiguous one will also be added.  This
     means that the resulting string is the longest unambiguous string
     possible.  However, menu completion can be used to cycle through
     all matches.

fake
     This style may be set for any completion context.  It specifies
     additional strings that will always be completed in that context.
     The form of each string is `VALUE:DESCRIPTION'; the colon and
     description may be omitted, but any literal colons in VALUE must
     be quoted with a backslash.  Any DESCRIPTION provided is shown
     alongside the value in completion listings.

     It is important to use a sufficiently restrictive context when
     specifying fake strings.  Note that the styles fake-files and
     fake-parameters provide additional features when completing files
     or parameters.

fake-always
     This works identically to the fake style except that the
     ignored-patterns style is not applied to it.  This makes it
     possible to override a set of matches completely by setting the
     ignored patterns to `*'.

     The following shows a way of supplementing any tag with arbitrary
     data, but having it behave for display purposes like a separate
     tag.  In this example we use the features of the tag-order style
     to divide the named-directories tag into two when performing
     completion with the standard completer complete for arguments of
     cd.  The tag named-directories-normal behaves as normal, but the
     tag named-directories-mine contains a fixed set of directories.
     This has the effect of adding the match group `extra directories'
     with the given completions.


          zstyle ':completion::complete:cd:*' tag-order \
            'named-directories:-mine:extra\ directories
            named-directories:-normal:named\ directories *'
          zstyle ':completion::complete:cd:*:named-directories-mine' \
            fake-always mydir1 mydir2
          zstyle ':completion::complete:cd:*:named-directories-mine' \
            ignored-patterns '*'

fake-files
     This style is used when completing files and looked up without a
     tag.  Its values are of the form `DIR:NAMES...'.  This will add
     the NAMES (strings separated by spaces) as possible matches when
     completing in the directory DIR, even if no such files really
     exist.  The dir may be a pattern; pattern characters or colons in
     DIR should be quoted with a backslash to be treated literally.

     This can be useful on systems that support special file systems
     whose top-level pathnames can not be listed or generated with glob
     patterns.  It can also be used for directories for which one does
     not have read permission.

     The pattern form can be used to add a certain `magic' entry to all
     directories on a particular file system.

fake-parameters
     This is used by the completion function for parameter names.  Its
     values are names of parameters that might not yet be set but
     should be completed nonetheless.  Each name may also be followed
     by a colon and a string specifying the type of the parameter (like
     `scalar', `array' or `integer').  If the type is given, the name
     will only be completed if parameters of that type are required in
     the particular context.  Names for which no type is specified will
     always be completed.

file-list
     This style controls whether files completed using the standard
     builtin mechanism are to be listed with a long list similar to ls
     -l.  Note that this feature uses the shell module zsh/stat for
     file information; this loads the builtin stat which will replace
     any external stat executable.  To avoid this the following code
     can be included in an initialization file:


          zmodload -i zsh/stat
          disable stat

     The style may either be set to a true value (or `all'), or one of
     the values `insert' or `list', indicating that files are to be
     listed in long format in all circumstances, or when attempting to
     insert a file name, or when listing file names without attempting
     to insert one.

     More generally, the value may be an array of any of the above
     values, optionally followed by =NUM.  If NUM is present it gives
     the maximum number of matches for which long listing style will be
     used.  For example,


          zstyle ':completion:*' file-list list=20 insert=10

     specifies that long format will be used when listing up to 20 files
     or inserting a file with up to 10 matches (assuming a listing is
     to be shown at all, for example on an ambiguous completion), else
     short format will be used.


          zstyle -e ':completion:*' file-list '(( ${+NUMERIC} )) && reply=(true)'

     specifies that long format will be used any time a numeric
     argument is supplied, else short format.

file-patterns
     This is used by the standard function for completing filenames,
     _files.  If the style is unset up to three tags are offered,
     `globbed-files',`directories' and `all-files', depending on the
     types of files  expected by the caller of _files.  The first two
     (`globbed-files' and `directories') are normally offered together
     to make it easier to complete files in sub-directories.

     The file-patterns style provides alternatives to the default tags,
     which are not used.  Its value consists of elements of the form
     `PATTERN:TAG'; each string may contain any number of such
     specifications separated by spaces.

     The PATTERN is a pattern that is to be used to generate filenames.
     Any occurrence of the sequence `%p' is replaced by any pattern(s)
     passed by the function calling _files.  Colons in the pattern must
     be preceded by a backslash to make them distinguishable from the
     colon before the TAG.  If more than one pattern is needed, the
     patterns can be given inside braces, separated by commas.

     The TAGs of all strings in the value will be offered by _files and
     used when looking up other styles.  Any TAGs in the same word will
     be offered at the same time and before later words.  If no `:TAG'
     is given the `files' tag will be used.

     The TAG may also be followed by an optional second colon and a
     description, which will be used for the `%d' in the value of the
     format style (if that is set) instead of the default description
     supplied by the completion function.  If the description given
     here contains itself a `%d', that is replaced with the description
     supplied by the completion function.

     For example, to make the rm command first complete only names of
     object files and then the names of all files if there is no
     matching object file:


          zstyle ':completion:*:*:rm:*' file-patterns \
              '*.o:object-files' '%p:all-files'

     To alter the default behaviour of file completion -- offer files
     matching a pattern and directories on the first attempt, then all
     files -- to offer only matching files on the first attempt, then
     directories, and finally all files:


          zstyle ':completion:*' file-patterns \
              '%p:globbed-files' '*(-/):directories' '*:all-files'

     This works even where there is no special pattern: _files matches
     all files using the pattern `*' at the first step and stops when it
     sees this pattern.  Note also it will never try a pattern more
     than once for a single completion attempt.

     During the execution of completion functions, the EXTENDED_GLOB
     option is in effect, so the characters `#', `~' and `^' have
     special meanings in the patterns.

file-sort
     The standard filename completion function uses this style without
     a tag to determine in which order the names should be listed; menu
     completion will cycle through them in the same order.  The possible
     values are: `size' to sort by the size of the file; `links' to
     sort by the number of links to the file; `modification' (or `time'
     or `date') to sort by the last modification time; `access' to sort
     by the last access time; and `inode' (or `change') to sort by the
     last inode change time.  If the style is set to any other value,
     or is unset, files will be sorted alphabetically by name.  If the
     value contains the string `reverse', sorting is done in the
     opposite order.  If the value contains the string `follow',
     timestamps are associated with the targets of symbolic links; the
     default is to use the timestamps of the links themselves.

filter
     This is used by the LDAP plugin for e-mail address completion to
     specify the attributes to match against when filtering entries.
     So for example, if the style is set to `sn', matching is done
     against surnames.  Standard LDAP filtering is used so normal
     completion matching is bypassed.  If this style is not set, the
     LDAP plugin is skipped.  You may also need to set the command
     style to specify how to connect to your LDAP server.

force-list
     This forces a list of completions to be shown at any point where
     listing is done, even in cases where the list would usually be
     suppressed.  For example, normally the list is only shown if there
     are at least two different matches.  By setting this style to
     `always', the list will always be shown, even if there is only a
     single match that will immediately be accepted.  The style may also
     be set to a number.  In this case the list will be shown if there
     are at least that many matches, even if they would all insert the
     same string.

     This style is tested for the default tag as well as for each tag
     valid for the current completion.  Hence the listing can be forced
     only for certain types of match.

format
     If this is set for the descriptions tag, its value is used as a
     string to display above matches in completion lists.  The sequence
     `%d' in this string will be replaced with a short description of
     what these matches are.  This string may also contain the following
     sequences to specify output attributes, *note Prompt Expansion:::
     `%B', `%S', `%U', `%F', `%K' and their lower case counterparts, as
     well as `%{...%}'.  `%F', `%K' and `%{...%}' take arguments in the
     same form as prompt expansion.  Note that the %G sequence is not
     available; an argument to `%{' should be used instead.

     The style is tested with each tag valid for the current completion
     before it is tested for the descriptions tag.  Hence different
     format strings can be defined for different types of match.

     Note also that some completer functions define additional
     `%'-sequences.  These are described for the completer functions
     that make use of them.

     Some completion functions display messages that may be customised
     by setting this style for the messages tag.  Here, the `%d' is
     replaced with a message given by the completion function.

     Finally, the format string is looked up with the warnings tag, for
     use when no matches could be generated at all.  In this case the
     `%d' is replaced with the descriptions for the matches that were
     expected separated by spaces.  The sequence `%D' is replaced with
     the same descriptions separated by newlines.

     It is possible to use printf-style field width specifiers with `%d'
     and similar escape sequences.  This is handled by the zformat
     builtin command from the zsh/zutil module, see *note The zsh/zutil
     Module::.

glob
     This is used by the _expand completer.  If it is set to `true'
     (the default), globbing will be attempted on the words resulting
     from a previous substitution (see the substitute style) or else
     the original string from the line.

global
     If this is set to `true' (the default), the _expand_alias
     completer and bindable command will try to expand global aliases.

group-name
     The completion system can group different types of matches, which
     appear in separate lists.  This style can be used to give the
     names of groups for particular tags.  For example, in command
     position the completion system generates names of builtin and
     external commands, names of aliases, shell functions and
     parameters and reserved words as possible completions.  To have
     the external commands and shell functions listed separately:


          zstyle ':completion:*:*:-command-:*:commands' group-name commands
          zstyle ':completion:*:*:-command-:*:functions' group-name functions

     As a consequence, any match with the same tag will be displayed in
     the same group.

     If the name given is the empty string the name of the tag for the
     matches will be used as the name of the group.  So, to have all
     different types of matches displayed separately, one can just set:


          zstyle ':completion:*' group-name ''

     All matches for which no group name is defined will be put in a
     group named -default-.

group-order
     This style is additional to the group-name style to specify the
     order for display of the groups defined by that style (compare
     tag-order, which determines which completions appear at all).  The
     groups named are shown in the given order; any other groups are
     shown in the order defined by the completion function.

     For example, to have names of builtin commands, shell functions and
     external commands appear in that order when completing in command
     position:


          zstyle ':completion:*:*:-command-:*' group-order \
                 builtins functions commands

groups
     A list of names of UNIX groups.  If this is not set, group names
     are taken from the YP database or the file `/etc/group'.

hidden
     If this is set to true, matches for the given context will not be
     listed, although any description for the matches set with the
     format style will be shown.  If it is set to `all', not even the
     description will be displayed.

     Note that the matches will still be completed; they are just not
     shown in the list.  To avoid having matches considered as possible
     completions at all, the tag-order style can be modified as
     described below.

hosts
     A list of names of hosts that should be completed.  If this is not
     set, hostnames are taken from the file `/etc/hosts'.

hosts-ports
     This style is used by commands that need or accept hostnames and
     network ports.  The strings in the value should be of the form
     `HOST:PORT'.  Valid ports are determined by the presence of
     hostnames; multiple ports for the same host may appear.

ignore-line
     This is tested for each tag valid for the current completion.  If
     it is set to `true', none of the words that are already on the line
     will be considered as possible completions.  If it is set to
     `current', the word the cursor is on will not be considered as a
     possible completion.  The value `current-shown' is similar but only
     applies if the list of completions is currently shown on the
     screen.  Finally, if the style is set to `other', no word apart
     from the current one will be considered as a possible completion.

     The values `current' and `current-shown' are a bit like the
     opposite of the accept-exact style:  only strings with missing
     characters will be completed.

     Note that you almost certainly don't want to set this to `true' or
     `other' for a general context such as `:completion:*'.  This is
     because it would disallow completion of, for example, options
     multiple times even if the command in question accepts the option
     more than once.

ignore-parents
     The style is tested without a tag by the function completing
     pathnames in order to determine whether to ignore the names of
     directories already mentioned in the current word, or the name of
     the current working directory.  The value must include one or both
     of the following strings:


    parent
          The name of any directory whose path is already contained in
          the word on the line is ignored.  For example, when
          completing after foo/../, the directory foo will not be
          considered a valid completion.

    pwd
          The name of the current working directory will not be
          completed; hence, for example, completion after ../ will not
          use the name of the current directory.


     In addition, the value may include one or both of:


    ..
          Ignore the specified directories only when the word on the
          line contains the substring `../'.

    directory
          Ignore the specified directories only when names of
          directories are completed, not when completing names of files.


     Excluded values act in a similar fashion to values of the
     ignored-patterns style, so they can be restored to consideration by
     the _ignored completer.

extra-verbose
     If set, the completion listing is more verbose at the cost of a
     probable decrease in completion speed.  Completion performance
     will suffer if this style is set to `true'.

ignored-patterns
     A list of patterns; any trial completion matching one of the
     patterns will be excluded from consideration.  The _ignored
     completer can appear in the list of completers to restore the
     ignored matches.  This is a more configurable version of the shell
     parameter $fignore.

     Note that the EXTENDED_GLOB option is set during the execution of
     completion functions, so the characters `#', `~' and `^' have
     special meanings in the patterns.

insert
     This style is used by the _all_matches completer to decide whether
     to insert the list of all matches unconditionally instead of
     adding the list as another match.

insert-ids
     When completing process IDs, for example as arguments to the kill
     and wait builtins the name of a command may be converted to the
     appropriate process ID.  A problem arises when the process name
     typed is not unique.  By default (or if this style is set
     explicitly to `menu') the name will be converted immediately to a
     set of possible IDs, and menu completion will be started to cycle
     through them.

     If the value of the style is `single', the shell will wait until
     the user has typed enough to make the command unique before
     converting the name to an ID; attempts at completion will be
     unsuccessful until that point.  If the value is any other string,
     menu completion will be started when the string typed by the user
     is longer than the common prefix to the corresponding IDs.

insert-tab
     If this is set to `true', the completion system will insert a TAB
     character (assuming that was used to start completion) instead of
     performing completion when there is no non-blank character to the
     left of the cursor.  If it is set to `false', completion will be
     done even there.

     The value may also contain the substrings `pending' or
     `pending=VAL'.  In this case, the typed character will be inserted
     instead of starting completion when there is unprocessed input
     pending.  If a VAL is given, completion will not be done if there
     are at least that many characters of unprocessed input.  This is
     often useful when pasting characters into a terminal.  Note
     however, that it relies on the $PENDING special parameter from the
     zsh/zle module being set properly which is not guaranteed on all
     platforms.

     The default value of this style is `true' except for completion
     within vared builtin command where it is `false'.

insert-unambiguous
     This is used by the _match and _approximate completers.  These
     completers are often used with menu completion since the word typed
     may bear little resemblance to the final completion.  However, if
     this style is `true', the completer will start menu completion
     only if it could find no unambiguous initial string at least as
     long as the original string typed by the user.

     In the case of the _approximate completer, the completer field in
     the context will already have been set to one of correct-NUM or
     approximate-NUM, where NUM is the number of errors that were
     accepted.

     In the case of the _match completer, the style may also be set to
     the string `pattern'.  Then the pattern on the line is left
     unchanged if it does not match unambiguously.

keep-prefix
     This style is used by the _expand completer.  If it is `true', the
     completer will try to keep a prefix containing a tilde or parameter
     expansion.  Hence, for example, the string `~/f*' would be
     expanded to `~/foo' instead of `/home/user/foo'.  If the style is
     set to `changed' (the default), the prefix will only be left
     unchanged if there were other changes between the expanded words
     and the original word from the command line.  Any other value
     forces the prefix to be expanded unconditionally.

     The behaviour of expand when this style is true is to cause _expand
     to give up when a single expansion with the restored prefix is the
     same as the original; hence any remaining completers may be called.

last-prompt
     This is a more flexible form of the ALWAYS_LAST_PROMPT option.  If
     it is true, the completion system will try to return the cursor to
     the previous command line after displaying a completion list.  It
     is tested for all tags valid for the current completion, then the
     default tag.  The cursor will be moved back to the previous line
     if this style is `true' for all types of match.  Note that unlike
     the ALWAYS_LAST_PROMPT option this is independent of the numeric
     prefix argument.

known-hosts-files
     This style should contain a list of files to search for host names
     and (if the use-ip style is set) IP addresses in a format
     compatible with ssh known_hosts files.  If it is not set, the files
     /etc/ssh/ssh_known_hosts and ~/.ssh/known_hosts are used.

list
     This style is used by the _history_complete_word bindable command.
     If it is set to `true' it has no effect.  If it is set to `false'
     matches will not be listed.  This overrides the setting of the
     options controlling listing behaviour, in particular AUTO_LIST.
     The context always starts with `:completion:history-words'.

list-colors
     If the zsh/complist module is loaded, this style can be used to set
     color specifications.  This mechanism replaces the use of the
     ZLS_COLORS and ZLS_COLOURS parameters described in *note The
     zsh/complist Module::, but the syntax is the same.

     If this style is set for the default tag, the strings in the value
     are taken as specifications that are to be used everywhere.  If it
     is set for other tags, the specifications are used only for
     matches of the type described by the tag.  For this to work best,
     the group-name style must be set to an empty string.

     In addition to setting styles for specific tags, it is also
     possible to use group names specified explicitly by the group-name
     tag together with the `(group)' syntax allowed by the ZLS_COLORS
     and ZLS_COLOURS parameters and simply using the default tag.

     It is possible to use any color specifications already set up for
     the GNU version of the ls command:


          zstyle ':completion:*:default' list-colors ${(s.:.)LS_COLORS}

     The default colors are the same as for the GNU ls command and can
     be obtained by setting the style to an empty string (i.e. '').

list-dirs-first
     This is used by file completion.  If set, directories to be
     completed are listed separately from and before completion for
     other files, regardless of tag ordering.  In addition, the tag
     other-files is used in place of all-files for the remaining files,
     to indicate that no directories are presented with that tag.

list-grouped
     If this style is `true' (the default), the completion system will
     try to make certain completion listings more compact by grouping
     matches.  For example, options for commands that have the same
     description (shown when the verbose style is set to `true') will
     appear as a single entry.  However, menu selection can be used to
     cycle through all the matches.

list-packed
     This is tested for each tag valid in the current context as well
     as the default tag.  If it is set to `true', the corresponding
     matches appear in listings as if the LIST_PACKED option were set.
     If it is set to `false', they are listed normally.

list-prompt
     If this style is set for the default tag, completion lists that
     don't fit on the screen can be scrolled (see *note The
     zsh/complist Module::).  The value, if not the empty string, will
     be displayed after every screenful and the shell will prompt for a
     key press; if the style is set to the empty string, a default
     prompt will be used.

     The value may contain the escape sequences: `%l' or `%L', which
     will be replaced by the number of the last line displayed and the
     total number of lines; `%m' or `%M', the number of the  last match
     shown and the total number of matches; and `%p' and `%P', `Top'
     when at the beginning of the list, `Bottom' when at the end and the
     position shown as a percentage of the total length otherwise.  In
     each case the form with the uppercase letter will be replaced by a
     string of fixed width, padded to the  right with spaces, while the
     lowercase form will be replaced by a variable width string.  As in
     other prompt strings, the escape sequences `%S', `%s', `%B', `%b',
     `%U', `%u' for entering and leaving the display modes standout,
     bold and underline, and `%F', `%f', `%K', `%k' for changing the
     foreground background colour, are also available, as is the form
     `%{...%}' for enclosing escape sequences which display with zero
     (or, with a numeric argument, some other) width.

     After deleting this prompt the variable LISTPROMPT should be unset
     for the the removal to take effect.

list-rows-first
     This style is tested in the same way as the list-packed style and
     determines whether matches are to be listed in a rows-first
     fashion as if the LIST_ROWS_FIRST option were set.

list-suffixes
     This style is used by the function that completes filenames.  If
     it is true, and completion is attempted on a string containing
     multiple partially typed pathname components, all ambiguous
     components will be shown.  Otherwise, completion stops at the
     first ambiguous component.

list-separator
     The value of this style is used in completion listing to separate
     the string to complete from a description when possible (e.g. when
     completing options).  It defaults to `--' (two hyphens).

local
     This is for use with functions that complete URLs for which the
     corresponding files are available directly from the file system.
     Its value should consist of three strings: a hostname, the path to
     the default web pages for the server, and the directory name used
     by a user placing web pages within their home area.

     For example:


          zstyle ':completion:*' local toast \
              /var/http/public/toast public_html

     Completion after `http://toast/stuff/' will look for files in the
     directory /var/http/public/toast/stuff,  while completion after
     `http://toast/~yousir/' will look for files in the directory
     ~yousir/public_html.

mail-directory
     If set, zsh will assume that mailbox files can be found in the
     directory specified.  It defaults to `~/Mail'.

match-original
     This is used by the _match completer.  If it is set to only,
     _match will try to generate matches without inserting a `*' at the
     cursor position.  If set to any other non-empty value, it will
     first try to generate matches without inserting the `*' and if
     that yields no matches, it will try again with the `*' inserted.
     If it is unset or set to the empty string, matching will only be
     performed with the `*' inserted.

matcher
     This style is tested separately for each tag valid in the current
     context.  Its value is added to any match specifications given by
     the matcher-list style.  It should be in the form described in
     *note Completion Matching Control::.

matcher-list
     This style can be set to a list of match specifications that are to
     be applied everywhere. Match specifications are described in *note
     Completion Matching Control::.  The completion system will try
     them one after another for each completer selected.  For example,
     to try first simple completion and, if that generates no matches,
     case-insensitive completion:


          zstyle ':completion:*' matcher-list '' 'm:{a-zA-Z}={A-Za-z}'

     By default each specification replaces the previous one; however,
     if a specification is prefixed with +, it is added to the existing
     list.  Hence it is possible to create increasingly general
     specifications without repetition:


          zstyle ':completion:*' matcher-list '' '+m{a-z}={A-Z}' '+m{A-Z}={a-z}'

     It is possible to create match specifications valid for particular
     completers by using the third field of the context.  For example,
     to use the completers _complete and _prefix but only allow
     case-insensitive completion with _complete:


          zstyle ':completion:*' completer _complete _prefix
          zstyle ':completion:*:complete:*' matcher-list \
                 '' 'm:{a-zA-Z}={A-Za-z}'

     User-defined names, as explained for the completer style, are
     available.  This makes it possible to try the same completer more
     than once with different match specifications each time.  For
     example, to try normal completion without a match specification,
     then normal completion with case-insensitive matching, then
     correction, and finally partial-word completion:


          zstyle ':completion:*' completer _complete _correct _complete:foo
          zstyle ':completion:*:complete:*' matcher-list \
              '' 'm:{a-zA-Z}={A-Za-z}'
          zstyle ':completion:*:foo:*' matcher-list \
              'm:{a-zA-Z}={A-Za-z} r:|[-_./]=* r:|=*'

     If the style is unset in any context no match specification is
     applied.  Note also that some completers such as _correct and
     _approximate do not use the match specifications at all, though
     these completers will only ever be called once even if the
     matcher-list contains more than one element.

     Where multiple specifications are useful, note that the _entire_
     completion is done for each element of matcher-list, which can
     quickly reduce the shell's performance.  As a rough rule of thumb,
     one to three strings will give acceptable performance.  On the
     other hand, putting multiple space-separated values into the same
     string does not have an appreciable impact on performance.

     If there is no current matcher or it is empty, and the option
     NO_CASE_GLOB is in effect, the matching for files is performed
     case-insensitively in any case.  However, any matcher must
     explicitly specify case-insensitive matching if that is required.

max-errors
     This is used by the _approximate and _correct completer functions
     to determine the maximum number of errors to allow.  The completer
     will try to generate completions by first allowing one error, then
     two errors, and so on, until either a match or matches were found
     or the maximum number of errors given by this style has been
     reached.

     If the value for this style contains the string `numeric', the
     completer function will take any numeric argument as the maximum
     number of errors allowed. For example, with


          zstyle ':completion:*:approximate:::' max-errors 2 numeric

     two errors are allowed if no numeric argument is given, but with a
     numeric argument of six (as in `ESC-6 TAB'), up to six errors are
     accepted.  Hence with a value of `0 numeric', no correcting
     completion will be attempted unless a numeric argument is given.

     If the value contains the string `not-numeric', the completer will
     _not_ try to generate corrected completions when given a numeric
     argument, so in this case the number given should be greater than
     zero.  For example, `2 not-numeric' specifies that correcting
     completion with two errors will usually be performed, but if a
     numeric argument is given, correcting completion will not be
     performed.

     The default value for this style is `2 numeric'.

max-matches-width
     This style is used to determine the trade off between the width of
     the display used for matches and the width used for their
     descriptions when the verbose style is in effect.  The value gives
     the number of display columns to reserve for the matches.  The
     default is half the width of the screen.

     This has the most impact when several matches have the same
     description and so will be grouped together.  Increasing the style
     will allow more matches to be grouped together; decreasing it will
     allow more of the description to be visible.

menu
     If this is true in the context of any of the tags defined for the
     current completion menu completion will be used.  The value for a
     specific tag will take precedence over that for the `default' tag.

     If none of the values found in this way is true but at least one
     is set to `auto', the shell behaves as if the AUTO_MENU option is
     set.

     If one of the values is explicitly set to false, menu completion
     will be explicitly turned off, overriding the MENU_COMPLETE option
     and other settings.

     In the form `yes=NUM', where `yes' may be any of the true values
     (`yes', `true', `on' and `1'), menu completion will be turned on
     if there are at least NUM matches.  In the form `yes=long', menu
     completion will be turned on if the list does not fit on the
     screen.  This does not activate menu completion if the widget
     normally only lists completions, but menu completion can be
     activated in that case with the value `yes=long-list' (Typically,
     the value `select=long-list' described later is more useful as it
     provides control over scrolling.)

     Similarly, with any of the `false' values (as in `no=10'), menu
     completion will _not_ be used if there are NUM or more matches.

     The value of this widget also controls menu selection, as
     implemented by the zsh/complist module.  The following values may
     appear either alongside or instead of the values above.

     If the value contains the string `select', menu selection will be
     started unconditionally.

     In the form `select=NUM', menu selection will only be started if
     there are at least NUM matches.  If the values for more than one
     tag provide a number, the smallest number is taken.

     Menu selection can be turned off explicitly by defining a value
     containing the string`no-select'.

     It is also possible to start menu selection only if the list of
     matches does not fit on the screen by using the value
     `select=long'.  To start menu selection even if the current widget
     only performs listing, use the value `select=long-list'.

     To turn on menu completion or menu selection when a there are a
     certain number of matches _or_ the list of matches does not fit on
     the screen, both of `yes=' and `select=' may be given twice, once
     with a number and once with `long' or `long-list'.

     Finally, it is possible to activate two special modes of menu
     selection.  The word `interactive' in the value causes interactive
     mode to be entered immediately when menu selection is started; see
     *note The zsh/complist Module:: for a description of interactive
     mode.  Including the string `search' does the same for incremental
     search mode.  To select backward incremental search, include the
     string `search-backward'.

muttrc
     If set, gives the location of the mutt configuration file.  It
     defaults to `~/.muttrc'.

numbers
     This is used with the jobs tag.  If it is `true', the shell will
     complete job numbers instead of the shortest unambiguous prefix of
     the job command text.  If the value is a number, job numbers will
     only be used if that many words from the job descriptions are
     required to resolve ambiguities.  For example, if the value is
     `1', strings will only be used if all jobs differ in the first
     word on their command lines.

old-list
     This is used by the _oldlist completer.  If it is set to `always',
     then standard widgets which perform listing will retain the
     current list of matches, however they were generated; this can be
     turned off explicitly with the value `never', giving the behaviour
     without the _oldlist completer.  If the style is unset, or any
     other value, then the existing list of completions is displayed if
     it is not already; otherwise, the standard completion list is
     generated; this is the default behaviour of _oldlist.  However, if
     there is an old list and this style contains the name of the
     completer function that generated the list, then the old list will
     be used even if it was generated by a widget which does not do
     listing.

     For example, suppose you type ^Xc to use the _correct_word widget,
     which generates a list of corrections for the word under the
     cursor.  Usually, typing ^D would generate a standard list of
     completions for the word on the command line, and show that.  With
     _oldlist, it will instead show the list of corrections already
     generated.

     As another example consider the _match completer: with the
     insert-unambiguous style set to `true' it inserts only a common
     prefix string, if there is any.  However, this may remove parts of
     the original pattern, so that further completion could produce
     more matches than on the first attempt.  By using the _oldlist
     completer and setting this style to _match, the list of matches
     generated on the first attempt will be used again.

old-matches
     This is used by the _all_matches completer to decide if an old
     list of matches should be used if one exists.  This is selected by
     one of the `true' values or by the string `only'.  If the value is
     `only', _all_matches will only use an old list and won't have any
     effect on the list of matches currently being generated.

     If this style is set it is generally unwise to call the
     _all_matches completer unconditionally.  One possible use is for
     either this style or the completer style to be defined with the -e
     option to zstyle to make the style conditional.

old-menu
     This is used by the _oldlist completer.  It controls how menu
     completion behaves when a completion has already been inserted and
     the user types a standard completion key such as TAB.  The default
     behaviour of _oldlist is that menu completion always continues
     with the existing list of completions.  If this style is set to
     `false', however, a new completion is started if the old list was
     generated by a different completion command; this is the behaviour
     without the _oldlist completer.

     For example, suppose you type ^Xc to generate a list of
     corrections, and menu completion is started in one of the usual
     ways.  Usually, or with this style set to false, typing TAB at
     this point would start trying to complete the line as it now
     appears.  With _oldlist, it instead continues to cycle through the
     list of corrections.

original
     This is used by the _approximate and _correct completers to decide
     if the original string should be added as a possible completion.
     Normally, this is done only if there are at least two possible
     corrections, but if this style is set to `true', it is always
     added.  Note that the style will be examined with the completer
     field in the context name set to correct-NUM or approximate-NUM,
     where NUM is the number of errors that were accepted.

packageset
     This style is used when completing arguments of the Debian `dpkg'
     program.  It contains an override for the default package set for
     a given context.  For example,


          zstyle ':completion:*:complete:dpkg:option--status-1:*' \
                         packageset avail

     causes available packages, rather than only installed packages, to
     be completed for `dpkg --status'.

path
     The function that completes color names uses this style with the
     colors tag.  The value should be the pathname of a file containing
     color names in the format of an X11 rgb.txt file.  If the style is
     not set but this file is found in one of various standard
     locations it will be used as the default.

path-completion
     This is used by filename completion.  By default, filename
     completion examines all components of a path to see if there are
     completions of that component.  For example, /u/b/z can be
     completed to /usr/bin/zsh.  Explicitly setting this style to false
     inhibits this behaviour for path components up to the / before the
     cursor; this overrides the setting of accept-exact-dirs.

     Even with the style set to false, it is still possible to complete
     multiple paths by setting the option COMPLETE_IN_WORD and moving
     the cursor back to the first component in the path to be
     completed.  For example, /u/b/z can be completed to /usr/bin/zsh
     if the cursor is after the /u.

pine-directory
     If set, specifies the directory containing PINE mailbox files.
     There is no default, since recursively searching this directory is
     inconvenient for anyone who doesn't use PINE.

ports
     A list of Internet service names (network ports) to complete.  If
     this is not set, service names are taken from the file
     `/etc/services'.

prefix-hidden
     This is used for certain completions which share a common prefix,
     for example command options beginning with dashes.  If it is
     `true', the prefix will not be shown in the list of matches.

     The default value for this style is `false'.

prefix-needed
     This, too, is used for matches with a common prefix.  If it is set
     to `true' this common prefix must be typed by the user to generate
     the matches.  In the case of command options, this means that the
     initial `-', `+', or `--' must be typed explicitly before option
     names will be completed.

     The default value for this style is `true'.

preserve-prefix
     This style is used when completing path names.  Its value should
     be a pattern matching an initial prefix of the word to complete
     that should be left unchanged under all circumstances.  For
     example, on some Unices an initial `//' (double slash) has a
     special meaning; setting this style to the string `//' will
     preserve it.  As another example, setting this style to `?:/'
     under Cygwin would allow completion after `a:/...' and so on.

range
     This is used by the _history completer and the
     _history_complete_word bindable command to decide which words
     should be completed.

     If it is a singe number, only the last N words from the history
     will be completed.

     If it is a range of the form `MAX:SLICE', the last SLICE words
     will be completed; then if that yields no matches, the SLICE words
     before those will be tried and so on.  This process stops either
     when at least one match was been found, or MAX words have been
     tried.

     The default is to complete all words from the history at once.

regular
     This style is used by the _expand_alias completer and bindable
     command.  If set to `true' (the default), regular aliases will be
     expanded but only in command position.  If it is set to `false',
     regular aliases will never be expanded.   If it is set to `always',
     regular aliases will be expanded even if not in command position.

rehash
     If this is set when completing external commands, the internal
     list (hash) of commands will be updated for each search by issuing
     the rehash command.  There is a speed penalty for this which is
     only likely to be noticeable when directories in the path have
     slow file access.

remote-access
     If set to false, certain commands will be prevented from making
     Internet connections to retrieve remote information.  This
     includes the completion for the CVS command.

     It is not always possible to know if connections are in fact to a
     remote site, so some may be prevented unnecessarily.

remove-all-dups
     The _history_complete_word bindable command and the _history
     completer use this to decide if all duplicate matches should be
     removed, rather than just consecutive duplicates.

select-prompt
     If this is set for the default tag, its value will be displayed
     during menu selection (see the menu style above) when the
     completion list does not fit on the screen as a whole.  The same
     escapes as for the list-prompt style are understood, except that
     the numbers refer to the match or line the mark is on.  A default
     prompt is used when the value is the empty string.

select-scroll
     This style is tested for the default tag and determines how a
     completion list is scrolled during a menu selection (see the menu
     style above) when the completion list does not fit on the screen
     as a whole.  If the value is `0' (zero), the list is scrolled by
     half-screenfuls; if it is a positive integer, the list is scrolled
     by the given number of lines; if it is a negative number, the list
     is scrolled by a screenful minus the absolute value of the given
     number of lines.  The default is to scroll by single lines.

separate-sections
     This style is used with the manuals tag when completing names of
     manual pages.  If it is `true', entries for different sections are
     added separately using tag names of the form `manual.X', where X
     is the section number.  When the group-name style is also in
     effect, pages from different sections will appear separately.
     This style is also used similarly with the words style when
     completing words for the dict command. It allows words from
     different dictionary databases to be added separately.  The
     default for this style is `false'.

show-completer
     Tested whenever a new completer is tried.  If it is true, the
     completion system outputs a progress message in the listing area
     showing what completer is being tried.  The message will be
     overwritten by any output when completions are found and is
     removed after completion is finished.

single-ignored
     This is used by the _ignored completer when there is only one
     match.  If its value is `show', the single match will be displayed
     but not inserted.  If the value is `menu', then the single match
     and the original string are both added as matches and menu
     completion is started, making it easy to select either of them.

sort
     Many completion widgets call _description at some point which
     decides whether the matches are added sorted or unsorted (often
     indirectly via _wanted or _requested).  This style can be set
     explicitly to one of the usual true or false values as an override.
     If it is not set for the context, the standard behaviour of the
     calling widget is used.

     The style is tested first against the full context including the
     tag, and if that fails to produce a value against the context
     without the tag.

     If the calling widget explicitly requests unsorted matches, this
     is usually honoured.  However, the default (unsorted) behaviour of
     completion for the command history may be overridden by setting
     the style to true.

     In the _expand completer, if it is set to `true', the expansions
     generated will always be sorted.  If it is set to `menu', then the
     expansions are only sorted when they are offered as single strings
     but not in the string containing all possible expansions.

special-dirs
     Normally, the completion code will not produce the directory names
     `.' and `..' as possible completions.  If this style is set to
     `true', it will add both `.' and `..' as possible completions; if
     it is set to `..', only `..' will be added.

     The following example sets special-dirs to `..' when the current
     prefix is empty, is a single `.', or consists only of a path
     beginning with `../'.  Otherwise the value is `false'.


          zstyle -e ':completion:*' special-dirs \
             '[[ $PREFIX = (../)#(|.|..) ]] && reply=(..)'

squeeze-slashes
     If set to `true', sequences of slashes in filename paths (for
     example in `foo//bar') will be treated as a single slash.  This is
     the usual behaviour of UNIX paths.  However, by default the file
     completion function behaves as if there were a `*' between the
     slashes.

stop
     If set to `true', the _history_complete_word bindable command will
     stop once when reaching the beginning or end of the history.
     Invoking _history_complete_word will then wrap around to the
     opposite end of the history.  If this style is set to `false' (the
     default), _history_complete_word will loop immediately as in a
     menu completion.

strip-comments
     If set to `true', this style causes non-essential comment text to
     be removed from completion matches.  Currently it is only used when
     completing e-mail addresses where it removes any display name from
     the addresses, cutting them down to plain USER@HOST form.

subst-globs-only
     This is used by the _expand completer.  If it is set to `true',
     the expansion will only be used if it resulted from globbing;
     hence, if expansions resulted from the use of the substitute style
     described below, but these were not further changed by globbing,
     the expansions will be rejected.

     The default for this style is `false'.

substitute
     This boolean style controls whether the _expand completer will
     first try to expand all substitutions in the string (such as
     `$(...)' and `${...}').

     The default is `true'.

suffix
     This is used by the _expand completer if the word starts with a
     tilde or contains a parameter expansion.  If it is set to `true',
     the word will only be expanded if it doesn't have a suffix, i.e.
     if it is something like `~foo' or `$foo' rather than `~foo/' or
     `$foo/bar', unless that suffix itself contains characters eligible
     for expansion.  The default for this style is `true'.

tag-order
     This provides a mechanism for sorting how the tags available in a
     particular context will be used.

     The values for the style are sets of space-separated lists of tags.
     The tags in each value will be tried at the same time; if no match
     is found, the next value is used.  (See the file-patterns style for
     an exception to this behavior.)

     For example:


          zstyle ':completion:*:complete:-command-:*' tag-order \
              'commands functions'

     specifies that completion in command position first offers
     external commands and shell functions.  Remaining tags will be
     tried if no completions are found.

     In addition to tag names, each string in the value may take one of
     the following forms:


    -
          If any value consists of only a hyphen, then _only_ the tags
          specified in the other values are generated.  Normally all
          tags not explicitly selected are tried last if the specified
          tags fail to generate any matches.  This means that a single
          value consisting only of a single hyphen turns off completion.

    ! TAGS...
          A string starting with an exclamation mark specifies names of
          tags that are _not_ to be used.  The effect is the same as if
          all other possible tags for the context had been listed.

    TAG:LABEL ...
          Here, TAG is one of the standard tags and LABEL is an
          arbitrary name.  Matches are generated as normal but the name
          LABEL is used in contexts instead of TAG.  This is not useful
          in words starting with !.

          If the LABEL starts with a hyphen, the TAG is prepended to the
          LABEL to form the name used for lookup.  This can be used to
          make the completion system try a certain tag more than once,
          supplying different style settings for each attempt; see
          below for an example.

    TAG:LABEL:DESCRIPTION
          As before, but description will replace the `%d' in the value
          of the format style instead of the default description
          supplied by the completion function.  Spaces in the
          description must be quoted with a backslash.  A `%d' appearing
          in DESCRIPTION is replaced with the description given by the
          completion function.


     In any of the forms above the tag may be a pattern or several
     patterns in the form `{PAT1,PAT2...}'.  In this case all matching
     tags will be used except for any given explicitly in the same
     string.

     One use of these features is to try one tag more than once,
     setting other styles differently on each attempt, but still to use
     all the other tags without having to repeat them all.  For
     example, to make completion of function names in command position
     ignore all the completion functions starting with an underscore
     the first time completion is tried:


          zstyle ':completion:*:*:-command-:*' tag-order \
              'functions:-non-comp *' functions
          zstyle ':completion:*:functions-non-comp' ignored-patterns '_*'

     On the first attempt, all tags will be offered but the functions
     tag will be replaced by functions-non-comp.  The ignored-patterns
     style is set for this tag to exclude functions starting with an
     underscore.  If there are no matches, the second value of the
     tag-order style is used which completes functions using the default
     tag, this time presumably including all function names.

     The matches for one tag can be split into different groups.  For
     example:


          zstyle ':completion:*' tag-order \
              'options:-long:long\ options
               options:-short:short\ options
               options:-single-letter:single\ letter\ options'

          zstyle ':completion:*:options-long' ignored-patterns '[-+](|-|[^-]*)'
          zstyle ':completion:*:options-short' ignored-patterns '--*' '[-+]?'
          zstyle ':completion:*:options-single-letter' ignored-patterns '???*'

     With the group-names style set, options beginning with `--',
     options beginning with a single `-' or `+' but containing multiple
     characters, and single-letter options will be displayed in
     separate groups with different descriptions.

     Another use of patterns is to try multiple match specifications
     one after another.  The matcher-list style offers something
     similar, but it is tested very early in the completion system and
     hence can't be set for single commands nor for more specific
     contexts.  Here is how to try normal completion without any match
     specification and, if that generates no matches, try again with
     case-insensitive matching, restricting the effect to arguments of
     the command foo:


          zstyle ':completion:*:*:foo:*' tag-order '*' '*:-case'
          zstyle ':completion:*-case' matcher 'm:{a-z}={A-Z}'

     First, all the tags offered when completing after foo are tried
     using the normal tag name.  If that generates no matches, the
     second value of tag-order is used, which tries all tags again
     except that this time each has -case appended to its name for
     lookup of styles.  Hence this time the value for the matcher style
     from the second call to zstyle in the example is used to make
     completion case-insensitive.

     It is possible to use the -e option of the zstyle builtin command
     to specify conditions for the use of particular tags.  For example:


          zstyle -e '*:-command-:*' tag-order '
              if [[ -n $PREFIX$SUFFIX ]]; then
                reply=( )
              else
                reply=( - )
              fi'

     Completion in command position will be attempted only if the string
     typed so far is not empty.  This is tested using the PREFIX
     special parameter; see *note Completion Widgets:: for a
     description of parameters which are special inside completion
     widgets.  Setting reply to an empty array provides the default
     behaviour of trying all tags at once; setting it to an array
     containing only a hyphen disables the use of all tags and hence of
     all completions.

     If no tag-order style has been defined for a context, the strings
     `(|*-)argument-* (|*-)option-* values' and `options' plus all tags
     offered by the completion function will be used to provide a
     sensible default behavior that causes arguments (whether normal
     command arguments or arguments of options) to be completed before
     option names for most commands.

urls
     This is used together with the the urls tag by functions
     completing URLs.

     If the value consists of more than one string, or if the only
     string does not name a file or directory, the strings are used as
     the URLs to complete.

     If the value contains only one string which is the name of a normal
     file the URLs are taken from that file (where the URLs may be
     separated by white space or newlines).

     Finally, if the only string in the value names a directory, the
     directory hierarchy rooted at this directory gives the
     completions.  The top level directory should be the file access
     method, such as `http', `ftp', `bookmark' and so on.  In many
     cases the next level of directories will be a filename.  The
     directory hierarchy can descend as deep as necessary.

     For example,


          zstyle ':completion:*' urls ~/.urls
          mkdir -p ~/.urls/ftp/ftp.zsh.org/pub/development

     allows completion of all the components of the URL
     ftp://ftp.zsh.org/pub/development after suitable commands such as
     `netscape' or `lynx'.  Note, however, that access methods and
     files are completed separately, so if the hosts style is set hosts
     can be completed without reference to the urls style.

     See the description in the function _urls itself for more
     information (e.g. `more $^fpath/_urls(N)').

use-cache
     If this is set, the completion caching layer is activated for any
     completions which use it (via the _store_cache, _retrieve_cache,
     and _cache_invalid functions).  The directory containing the cache
     files can be changed with the cache-path style.

use-compctl
     If this style is set to a string _not_ equal to false, 0, no, and
     off, the completion system may use any completion specifications
     defined with the compctl builtin command.  If the style is unset,
     this is done only if the zsh/compctl module is loaded.  The string
     may also contain the substring `first' to use completions defined
     with `compctl -T', and the substring `default' to use the
     completion defined with `compctl -D'.

     Note that this is only intended to smooth the transition from
     compctl to the new completion system and may disappear in the
     future.

     Note also that the definitions from compctl will only be used if
     there is no specific completion function for the command in
     question.  For example, if there is a function _foo to complete
     arguments to the command foo, compctl will never be invoked for
     foo.  However, the compctl version will be tried if foo only uses
     default completion.

use-ip
     By default, the function _hosts that completes host names strips
     IP addresses from entries read from host databases such as NIS and
     ssh files.  If this style is true, the corresponding IP addresses
     can be completed as well.  This style is not use in any context
     where the hosts style is set; note also it must be set before the
     cache of host names is generated (typically the first completion
     attempt).

use-perl
     Various parts of the function system use awk to extract words from
     files or command output as it is universally available.  However,
     many versions of awk have arbitrary limits on the size of input.
     If this style is set, perl will be used instead.  This is almost
     always preferable if perl is available on your system.

     Currently this is only used in completions for `make', but it may
     be extended depending on authorial frustration.

users
     This may be set to a list of usernames to be completed.  If it is
     not set all usernames will be completed.  Note that if it is set
     only that list of users will be completed; this is because on some
     systems querying all users can take a prohibitive amount of time.

users-hosts
     The values of this style should be of the form `USER@HOST' or
     `USER:HOST'. It is used for commands that need pairs of user- and
     hostnames.  These commands will complete usernames from this style
     (only), and will restrict subsequent hostname completion to hosts
     paired with that user in one of the values of the style.

     It is possible to group values for sets of commands which allow a
     remote login, such as rlogin and ssh, by using the my-accounts tag.
     Similarly, values for sets of commands which usually refer to the
     accounts of other people, such as talk and finger, can be grouped
     by using the other-accounts tag.  More ambivalent commands may use
     the accounts tag.

users-hosts-ports
     Like users-hosts but used for commands like telnet and containing
     strings of the form `USER@HOST:PORT'.

verbose
     If set, as it is by default, the completion listing is more
     verbose.  In particular many commands show descriptions for
     options if this style is `true'.

word
     This is used by the _list completer, which prevents the insertion
     of completions until a second completion attempt when the line has
     not changed.  The normal way of finding out if the line has
     changed is to compare its entire contents between the two
     occasions.  If this style is true, the comparison is instead
     performed only on the current word.  Hence if completion is
     performed on another word with the same contents, completion will
     not be delayed.



File: zsh.info,  Node: Control Functions,  Next: Bindable Commands,  Prev: Completion System Configuration,  Up: Completion System

20.4 Control Functions
======================



The initialization script compinit redefines all the widgets which
perform completion to call the supplied widget function _main_complete.
This function acts as a wrapper calling the so-called `completer'
functions that generate matches.  If _main_complete is called with
arguments, these are taken as the names of completer functions to be
called in the order given.  If no arguments are given, the set of
functions to try is taken from the completer style.  For example, to
use normal completion and correction if that doesn't generate any
matches:


     zstyle ':completion:*' completer _complete _correct

after calling compinit. The default value for this style is `_complete
_ignored', i.e. normally only ordinary completion is tried, first with
the effect of the ignored-patterns style and then without it.  The
_main_complete function uses the return status of the completer
functions to decide if other completers should be called.  If the return
status is zero, no other completers are tried and the _main_complete
function returns.

If the first argument to _main_complete is a single hyphen, the
arguments will not be taken as names of completers.  Instead, the
second argument gives a name to use in the COMPLETER field of the
context and the other arguments give a command name and arguments to
call to generate the matches.

The following completer functions are contained in the distribution,
although users may write their own.  Note that in contexts the leading
underscore is stripped, for example basic completion is performed in the
context `:completion::complete:...'.


_all_matches
     This completer can be used to add a string consisting of all other
     matches.  As it influences later completers it must appear as the
     first completer in the list.  The list of all matches is affected
     by the avoid-completer and old-matches styles described above.

     It may be useful to use the _generic function described below to
     bind _all_matches to its own keystroke, for example:


          zle -C all-matches complete-word _generic
          bindkey '^Xa' all-matches
          zstyle ':completion:all-matches:*' old-matches only
          zstyle ':completion:all-matches::::' completer _all_matches

     Note that this does not generate completions by itself:  first use
     any of the standard ways of generating a list of completions, then
     use ^Xa to show all matches.  It is possible instead to add a
     standard completer to the list and request that the list of all
     matches should be directly inserted:


          zstyle ':completion:all-matches::::' completer _all_matches _complete
          zstyle ':completion:all-matches:*' insert true

     In this case the old-matches style should not be set.

_approximate
     This is similar to the basic _complete completer but allows the
     completions to undergo corrections.  The maximum number of errors
     can be specified by the max-errors style; see the description of
     approximate matching in *note Filename Generation:: for how errors
     are counted.  Normally this completer will only be tried after the
     normal _complete completer:


          zstyle ':completion:*' completer _complete _approximate

     This will give correcting completion if and only if normal
     completion yields no possible completions.  When corrected
     completions are found, the completer will normally start menu
     completion allowing you to cycle through these strings.

     This completer uses the tags corrections and original when
     generating the possible corrections and the original string.  The
     format style for the former may contain the additional sequences
     `%e' and `%o' which will be replaced by the number of errors
     accepted to generate the corrections and the original string,
     respectively.

     The completer progressively increases the number of errors allowed
     up to the limit by the max-errors style, hence if a completion is
     found with one error, no completions with two errors will be
     shown, and so on.  It modifies the completer name in the context
     to indicate the number of errors being tried: on the first try the
     completer field contains `approximate-1', on the second try
     `approximate-2', and so on.

     When _approximate is called from another function, the number of
     errors to accept may be passed with the -a option.  The argument
     is in the same format as the max-errors style, all in one string.

     Note that this completer (and the _correct completer mentioned
     below) can be quite expensive to call, especially when a large
     number of errors are allowed.  One way to avoid this is to set up
     the completer style using the -e option to zstyle so that some
     completers are only used when completion is attempted a second
     time on the same string, e.g.:


          zstyle -e ':completion:*' completer '
            if [[ $_last_try != "$HISTNO$BUFFER$CURSOR" ]]; then
              _last_try="$HISTNO$BUFFER$CURSOR"
              reply=(_complete _match _prefix)
            else
              reply=(_ignored _correct _approximate)
            fi'

     This uses the HISTNO parameter and the BUFFER and CURSOR special
     parameters that are available inside zle and completion widgets to
     find out if the command line hasn't changed since the last time
     completion was tried.  Only then are the _ignored, _correct and
     _approximate completers called.

_complete
     This completer generates all possible completions in a
     context-sensitive manner, i.e. using the settings defined with the
     compdef function explained above and the current settings of all
     special parameters.  This gives the normal completion behaviour.

     To complete arguments of commands, _complete uses the utility
     function _normal, which is in turn responsible for finding the
     particular function; it is described below.  Various contexts of
     the form -CONTEXT- are handled specifically. These are all
     mentioned above as possible arguments to the #compdef tag.

     Before trying to find a function for a specific context, _complete
     checks if the parameter `compcontext' is set. Setting
     `compcontext' allows the usual completion dispatching to be
     overridden which is useful in places such as a function that uses
     vared for input. If it is set to an array, the elements are taken
     to be the possible matches which will be completed using the tag
     `values' and the description `value'. If it is set to an
     associative array, the keys are used as the possible completions
     and the values (if non-empty) are used as descriptions for the
     matches.  If `compcontext' is set to a string containing colons,
     it should be of the form `TAG:DESCR:ACTION'.  In this case the TAG
     and DESCR give the tag and description to use and the ACTION
     indicates what should be completed in one of the forms accepted by
     the _arguments utility function described below.

     Finally, if `compcontext' is set to a string without colons, the
     value is taken as the name of the context to use and the function
     defined for that context will be called.  For this purpose, there
     is a special context named -command-line- that completes whole
     command lines (commands and their arguments).  This is not used by
     the completion system itself but is nonetheless handled when
     explicitly called.

_correct
     Generate corrections, but not completions, for the current word;
     this is similar to _approximate but will not allow any number of
     extra characters at the cursor as that completer does.  The effect
     is similar to spell-checking.  It is based on _approximate, but the
     completer field in the context name is correct.

     For example, with:


          zstyle ':completion:::::' completer _complete _correct _approximate
          zstyle ':completion:*:correct:::' max-errors 2 not-numeric
          zstyle ':completion:*:approximate:::' max-errors 3 numeric

     correction will accept up to two errors.  If a numeric argument is
     given, correction will not be performed, but correcting completion
     will be, and will accept as many errors as given by the numeric
     argument.  Without a numeric argument, first correction and then
     correcting completion will be tried, with the first one accepting
     two errors and the second one accepting three errors.

     When _correct is called as a function, the number of errors to
     accept may be given following the -a option.  The argument is in
     the same form a values to the accept style, all in one string.

     This completer function is intended to be used without the
     _approximate completer or, as in the example, just before it.
     Using it after the _approximate completer is useless since
     _approximate will at least generate the corrected strings
     generated by the _correct completer -- and probably more.

_expand
     This completer function does not really perform completion, but
     instead checks if the word on the command line is eligible for
     expansion and, if it is, gives detailed control over how this
     expansion is done.  For this to happen, the completion system
     needs to be invoked with complete-word, not expand-or-complete
     (the default binding for TAB), as otherwise the string will be
     expanded by the shell's internal mechanism before the completion
     system is started.  Note also this completer should be called
     before the _complete completer function.

     The tags used when generating expansions are all-expansions for the
     string containing all possible expansions, expansions when adding
     the possible expansions as single matches and original when adding
     the original string from the line.  The order in which these
     strings are generated, if at all, can be controlled by the
     group-order and tag-order styles, as usual.

     The format string for all-expansions and for expansions may
     contain the sequence `%o' which will be replaced by the original
     string from the line.

     The kind of expansion to be tried is controlled by the substitute,
     glob and subst-globs-only styles.

     It is also possible to call _expand as a function, in which case
     the different modes may be selected with options: -s for
     substitute, -g for glob and -o for subst-globs-only.

_expand_alias
     If the word the cursor is on is an alias, it is expanded and no
     other completers are called.  The types of aliases which are to be
     expanded can be controlled with the styles regular, global and
     disabled.

     This function is also a bindable command, see *note Bindable
     Commands::.

_history
     Complete words from the shell's command  history.  This completer
     can be controlled by the remove-all-dups, and sort styles as for
     the _history_complete_word bindable command, see *note Bindable
     Commands:: and *note Completion System Configuration::.

_ignored
     The ignored-patterns style can be set to a list of patterns which
     are compared against possible completions; matching ones are
     removed.  With this completer those matches can be reinstated, as
     if no ignored-patterns style were set.  The completer actually
     generates its own list of matches; which completers are invoked is
     determined in the same way as for the _prefix completer.  The
     single-ignored style is also available as described above.

_list
     This completer allows the insertion of matches to be delayed until
     completion is attempted a second time without the word on the line
     being changed.  On the first attempt, only the list of matches
     will be shown.  It is affected by the styles condition and word,
     see *note Completion System Configuration::.

_match
     This completer is intended to be used after the _complete
     completer.  It behaves similarly but the string on the command
     line may be a pattern to match against trial completions.  This
     gives the effect of the GLOB_COMPLETE option.

     Normally completion will be performed by taking the pattern from
     the line, inserting a `*' at the cursor position and comparing the
     resulting pattern with the possible completions generated.  This
     can be modified with the match-original style described above.

     The generated matches will be offered in a menu completion unless
     the insert-unambiguous style is set to `true'; see the description
     above for other options for this style.

     Note that matcher specifications defined globally or used by the
     completion functions (the styles matcher-list and matcher) will
     not be used.

_menu
     This completer was written as simple example function to show how
     menu completion can be enabled in shell code. However, it has the
     notable effect of disabling menu selection which can be useful with
     _generic based widgets. It should be used as the first completer in
     the list.  Note that this is independent of the setting of the
     MENU_COMPLETE option and does not work with the other menu
     completion widgets such as reverse-menu-complete, or
     accept-and-menu-complete.

_oldlist
     This completer controls how the standard completion widgets behave
     when there is an existing list of completions which may have been
     generated by a special completion (i.e. a separately-bound
     completion command).  It allows the ordinary completion keys to
     continue to use the list of completions thus generated, instead of
     producing a new list of ordinary contextual completions.  It
     should appear in the list of completers before any of the widgets
     which generate matches.  It uses two styles: old-list and
     old-menu, see *note Completion System Configuration::.

_prefix
     This completer can be used to try completion with the suffix
     (everything after the cursor) ignored.  In other words, the suffix
     will not be considered to be part of the word to complete.  The
     effect is similar to the expand-or-complete-prefix command.

     The completer style is used to decide which other completers are to
     be called to generate matches.  If this style is unset, the list of
     completers set for the current context is used -- except, of
     course, the _prefix completer itself.  Furthermore, if this
     completer appears more than once in the list of completers only
     those completers not already tried by the last invocation of
     _prefix will be called.

     For example, consider this global completer style:


          zstyle ':completion:*' completer \
              _complete _prefix _correct _prefix:foo

     Here, the _prefix completer tries normal completion but ignoring
     the suffix.  If that doesn't generate any matches, and neither does
     the call to the _correct completer after it, _prefix will be
     called a second time and, now only trying correction with the
     suffix ignored.  On the second invocation the completer part of the
     context appears as `foo'.

     To use _prefix as the last resort and try only normal completion
     when it is invoked:


          zstyle ':completion:*' completer _complete ... _prefix
          zstyle ':completion::prefix:*' completer _complete

     The add-space style is also respected.  If it is set to `true' then
     _prefix will insert a space between the matches generated (if any)
     and the suffix.

     Note that this completer is only useful if the COMPLETE_IN_WORD
     option is set; otherwise, the cursor will be moved to the end of
     the current word before the completion code is called and hence
     there will be no suffix.

_user_expand
     This completer behaves similarly to the _expand completer but
     instead performs expansions defined by users.  The styles
     add-space and sort styles specific to the _expand completer are
     usable with _user_expand in addition to other styles handled more
     generally by the completion system.  The tag all-expansions is
     also available.

     The expansion depends on the array style user-expand being defined
     for the current context; remember that the context for completers
     is less specific than that for contextual completion as the full
     context has not yet been determined.  Elements of the array may
     have one of the following forms:
    $HASH
          HASH is the name of an associative array.  Note this is not a
          full parameter expression, merely a $, suitably quoted to
          prevent immediate expansion, followed by the name of an
          associative array.  If the trial expansion word matches a key
          in HASH, the resulting expansion is the corresponding value.

    _FUNC
          _FUNC is the name of a shell function whose name must begin
          with _ but is not otherwise special to the completion system.
          The function is called with the trial word as an argument.
          If the word is to be expanded, the function should set the
          array reply to a list of expansions.  The return status of
          the function is irrelevant.




File: zsh.info,  Node: Bindable Commands,  Next: Completion Functions,  Prev: Control Functions,  Up: Completion System

20.5 Bindable Commands
======================



In addition to the context-dependent completions provided, which are
expected to work in an intuitively obvious way, there are a few widgets
implementing special behaviour which can be bound separately to keys.
The following is a list of these and their default bindings.


_bash_completions
     This function is used by two widgets, _bash_complete-word and
     _bash_list-choices.  It exists to provide compatibility with
     completion bindings in bash.  The last character of the binding
     determines what is completed: `!', command names; `$', environment
     variables; `@', host names; `/', file names; `~' user names.  In
     bash, the binding preceded by `\e' gives completion, and preceded
     by `^X' lists options.  As some of these bindings clash with
     standard zsh bindings, only `\e~' and `^X~' are bound by default.
     To add the rest, the following should be added to .zshrc after
     compinit has been run:


          for key in '!' '$' '@' '/' '~'; do
            bindkey "\e$key" _bash_complete-word
            bindkey "^X$key" _bash_list-choices
          done

     This includes the bindings for `~' in case they were already bound
     to something else; the completion code does not override user
     bindings.

_correct_filename (^XC)
     Correct the filename path at the cursor position.  Allows up to
     six errors in the name.  Can also be called with an argument to
     correct a filename path, independently of zle; the correction is
     printed on standard output.

_correct_word (^Xc)
     Performs correction of the current argument using the usual
     contextual completions as possible choices. This stores the string
     `correct-word' in the FUNCTION field of the context name and then
     calls the _correct completer.

_expand_alias (^Xa)
     This function can be used as a completer and as a bindable command.
     It expands the word the cursor is on if it is an alias.  The types
     of alias expanded can be controlled with the styles regular, global
     and disabled.

     When used as a bindable command there is one additional feature
     that can be selected by setting the complete style to `true'.  In
     this case, if the word is not the name of an alias, _expand_alias
     tries to complete the word to a full alias name without expanding
     it.  It leaves the cursor directly after the completed word so
     that invoking _expand_alias once more will expand the now-complete
     alias name.

_expand_word (^Xe)
     Performs expansion on the current word:  equivalent to the standard
     expand-word command, but using the _expand completer.  Before
     calling it, the FUNCTION field of the context is set to
     `expand-word'.

_generic
     This function is not defined as a widget and not bound by default.
     However, it can be used to define a widget and will then store the
     name of the widget in the FUNCTION field of the context and call
     the completion system.  This allows custom completion widgets with
     their own set of style settings to be defined easily.  For example,
     to define a widget that performs normal completion and starts menu
     selection:


          zle -C foo complete-word _generic
          bindkey '...' foo
          zstyle ':completion:foo:*' menu yes select=1

     Note in particular that the completer style may be set for the
     context in order to change the set of functions used to generate
     possible matches.  If _generic is called with arguments, those are
     passed through to _main_complete as the list of completers in
     place of those defined by the completer style.

_history_complete_word (\e/)
     Complete words from the shell's command history. This uses the
     list, remove-all-dups, sort, and stop styles.

_most_recent_file (^Xm)
     Complete the name of the most recently modified file matching the
     pattern on the command line (which may be blank).  If given a
     numeric argument N, complete the Nth most recently modified file.
     Note the completion, if any, is always unique.

_next_tags (^Xn)
     This command alters the set of matches used to that for the next
     tag, or set of tags, either as given by the tag-order style or as
     set by default; these matches would otherwise not be available.
     Successive invocations of the command cycle through all possible
     sets of tags.

_read_comp (^X^R)
     Prompt the user for a string, and use that to perform completion
     on the current word.  There are two possibilities for the string.
     First, it can be a set of words beginning `_', for example `_files
     -/', in which case the function with any arguments will be called
     to generate the completions.  Unambiguous parts of the function
     name will be completed automatically (normal completion is not
     available at this point) until a space is typed.

     Second, any other string will be passed as a set of arguments to
     compadd and should hence be an expression specifying what should
     be completed.

     A very restricted set of editing commands is available when
     reading the string:  `DEL' and `^H' delete the last character;
     `^U' deletes the line, and `^C' and `^G' abort the function, while
     `RET' accepts the completion.  Note the string is used verbatim as
     a command line, so arguments must be quoted in accordance with
     standard shell rules.

     Once a string has been read, the next call to _read_comp will use
     the existing string instead of reading a new one.  To force a new
     string to be read, call _read_comp with a numeric argument.

_complete_debug (^X?)
     This widget performs ordinary completion, but captures in a
     temporary file a trace of the shell commands executed by the
     completion system.  Each completion attempt gets its own file.  A
     command to view each of these files is pushed onto the editor
     buffer stack.

_complete_help (^Xh)
     This widget displays information about the context names, the
     tags, and the completion functions used when completing at the
     current cursor position. If given a numeric argument other than 1
     (as in `ESC-2 ^Xh'), then the styles used and the contexts for
     which they are used will be shown, too.

     Note that the information about styles may be incomplete; it
     depends on the information available from the completion functions
     called, which in turn is determined by the user's own styles and
     other settings.

_complete_help_generic
     Unlike other commands listed here, this must be created as a
     normal ZLE widget rather than a completion widget (i.e. with zle
     -N).  It is used for generating help with a widget bound to the
     _generic widget that is described above.

     If this widget is created using the name of the function, as it is
     by default, then when executed it will read a key sequence.  This
     is expected to be bound to a call to a completion function that
     uses the _generic widget.  That widget will be executed, and
     information provided in the same format that the _complete_help
     widget displays for contextual completion.

     If the widget's name contains debug, for example if it is created
     as `zle -N _complete_debug_generic _complete_help_generic', it
     will read and execute the keystring for a generic widget as before,
     but then generate debugging information as done by _complete_debug
     for contextual completion.

     If the widget's name contains noread, it will not read a keystring
     but instead arrange that the next use of a generic widget run in
     the same shell will have the effect as described above.

     The widget works by setting the shell parameter
     ZSH_TRACE_GENERIC_WIDGET which is read by _generic.  Unsetting the
     parameter cancels any pending effect of the noread form.

     For example, after executing the following:


          zle -N _complete_debug_generic _complete_help_generic
          bindkey '^x:' _complete_debug_generic

     typing `C-x :' followed by the key sequence for a generic widget
     will cause trace output for that widget to be saved to a file.

_complete_tag (^Xt)
     This widget completes symbol tags created by the etags or ctags
     programmes (note there is no connection with the completion
     system's tags) stored in a file TAGS, in the format used by etags,
     or tags, in the format created by ctags.  It will look back up the
     path hierarchy for the first occurrence of either file; if both
     exist, the file TAGS is preferred.  You can specify the full path
     to a TAGS or tags file by setting the parameter $TAGSFILE or
     $tagsfile respectively.  The corresponding completion tags used
     are etags and vtags, after emacs and vi respectively.



File: zsh.info,  Node: Completion Functions,  Next: Completion Directories,  Prev: Bindable Commands,  Up: Completion System

20.6 Utility Functions
======================



Descriptions follow for utility functions that may be useful when
writing completion functions.  If functions are installed in
subdirectories, most of these reside in the Base subdirectory.  Like
the example functions for commands in the distribution, the utility
functions generating matches all follow the convention of returning
status zero if they generated completions and non-zero if no matching
completions could be added.

Two more features are offered by the _main_complete function.  The
arrays compprefuncs and comppostfuncs may contain names of functions
that are to be called immediately before or after completion has been
tried.  A function will only be called once unless it explicitly
reinserts itself into the array.


_all_labels [ -x ] [ -12VJ ] TAG NAME DESCR [ COMMAND ARGS ... ]
     This is a convenient interface to the _next_label function below,
     implementing the loop shown in the _next_label example.  The
     COMMAND and its arguments are called to generate the matches.  The
     options stored in the parameter NAME will automatically be inserted
     into the ARGS passed to the COMMAND.  Normally, they are put
     directly after the COMMAND, but if one of the ARGS is a single
     hyphen, they are inserted directly before that.  If the hyphen is
     the last argument, it will be removed from the argument list
     before the COMMAND is called.  This allows _all_labels to be used
     in almost all cases where the matches can be generated by a single
     call to the compadd builtin command or by a call to one of the
     utility functions.

     For example:


          local expl
          ...
          if _requested foo; then
            ...
            _all_labels foo expl '...' compadd ... - $matches
          fi

     Will complete the strings from the matches parameter, using
     compadd with additional options which will take precedence over
     those generated by _all_labels.

_alternative [ -C NAME ] SPEC ...
     This function is useful in simple cases where multiple tags are
     available.  Essentially it implements a loop like the one
     described for the _tags function below.

     The tags to use and the action to perform if a tag is requested are
     described using the SPECs which are of the form:
     `TAG:DESCR:ACTION'.  The TAGs are offered using _tags and if the
     tag is requested, the ACTION is executed with the given
     description DESCR.  The ACTIONs are those accepted by the
     _arguments function (described below), excluding the `->STATE' and
     `=...' forms.

     For example, the ACTION may be a simple function call:


          _alternative \
              'users:user:_users' \
              'hosts:host:_hosts'

     offers usernames and hostnames as possible matches, generated by
     the _users and _hosts functions respectively.

     Like _arguments, this function uses _all_labels to execute the
     actions, which will loop over all sets of tags.  Special handling
     is only required if there is an additional valid tag, for example
     inside a function called from _alternative.

     Like _tags this function supports the -C option to give a
     different name for the argument context field.

_arguments [ -nswWACRS ] [ -O NAME ] [ -M MATCHSPEC ] [ : ] SPEC ...
     This function can be used to give a complete specification for
     completion for a command whose arguments follow standard UNIX
     option and argument conventions.  The following forms specify
     individual sets of options and arguments; to avoid ambiguity,
     these may be separated from the options to _arguments itself by a
     single colon.  Options to _arguments itself must be in separate
     words, i.e. -s -w, not -sw.

     With the option -n, _arguments sets the parameter NORMARG to the
     position of the first normal argument in the $words array, i.e.
     the position after the end of the options.  If that argument has
     not been reached, NORMARG is set to -1.  The caller should declare
     `integer NORMARG' if the -n option is passed; otherwise the
     parameter is not used.


    N:MESSAGE:ACTION
    N::MESSAGE:ACTION
          This describes the N'th normal argument.  The MESSAGE will be
          printed above the matches generated and the ACTION indicates
          what can be completed in this position (see below).  If there
          are two colons before the MESSAGE the argument is optional.
          If the MESSAGE contains only white space, nothing will be
          printed above the matches unless the action adds an
          explanation string itself.

    :MESSAGE:ACTION
    ::MESSAGE:ACTION
          Similar, but describes the _next_ argument, whatever number
          that happens to be.  If all arguments are specified in this
          form in the correct order the numbers are unnecessary.

    *:MESSAGE:ACTION
    *::MESSAGE:ACTION
    *:::MESSAGE:ACTION
          This describes how arguments (usually non-option arguments,
          those not beginning with - or +) are to be completed when
          neither of the first two forms was provided.  Any number of
          arguments can be completed in this fashion.

          With two colons before the MESSAGE, the words special array
          and the CURRENT special parameter are modified to refer only
          to the normal arguments when the ACTION is executed or
          evaluated.  With three colons before the MESSAGE they are
          modified to refer only to the normal arguments covered by
          this description.

    OPTSPEC
    OPTSPEC:...
          This describes an option.  The colon indicates handling for
          one or more arguments to the option; if it is not present,
          the option is assumed to take no arguments.

          By default, options are multi-character name, one `-WORD' per
          option.  With -s, options may be single characters, with more
          than one option per word, although words starting with two
          hyphens, such as `--prefix', are still considered complete
          option names.  This is suitable for standard GNU options.

          The combination of -s with -w allows single-letter options to
          be combined in a single word even if one or more of the
          options take arguments.  For example, if -a takes an
          argument, with no -s `-ab' is considered as a single
          (unhandled) option; with -s -ab is an option with the
          argument `b'; with both -s and -w, -ab may be the option -a
          and the option -b with arguments still to come.

          The option -W takes this a stage further:  it is possible to
          complete single-letter options even after an argument that
          occurs in the same word.  However, it depends on the action
          performed whether options will really be completed at this
          point.  For more control, use a utility function like _guard
          as part of the action.

          The following forms are available for the initial OPTSPEC,
          whether or not the option has arguments.


         *OPTSPEC
               Here OPTSPEC is one of the remaining forms below.  This
               indicates the following OPTSPEC may be repeated.
               Otherwise if the corresponding option is already present
               on the command line to the left of the cursor it will
               not be offered again.

         -OPTNAME
         +OPTNAME
               In the simplest form the OPTSPEC is just the option name
               beginning with a minus or a plus sign, such as `-foo'.
               The first argument for the option (if any) must follow
               as a _separate_ word directly after the option.

               Either of `-+OPTNAME' and `+-OPTNAME' can be used to
               specify that -OPTNAME and +OPTNAME are both valid.

               In all the remaining forms, the leading `-' may be
               replaced by or paired with `+' in this way.

         -OPTNAME-
               The first argument of the option must come directly
               after the option name _in the same word_.  For example,
               `-foo-:...' specifies that the completed option and
               argument will look like `-fooARG'.

         -OPTNAME+
               The first argument may appear immediately after OPTNAME
               in the same word, or may appear as a separate word after
               the option.  For example, `-foo+:...' specifies that the
               completed option and argument will look like either
               `-fooARG' or `-foo ARG'.

         -OPTNAME=
               The argument may appear as the next word, or in same
               word as the option name provided that it is separated
               from it by an equals sign, for example `-foo=ARG' or
               `-foo ARG'.

         -OPTNAME=-
               The argument to the option must appear after an equals
               sign in the same word, and may not be given in the next
               argument.

         OPTSPEC[EXPLANATION]
               An explanation string may be appended to any of the
               preceding forms of OPTSPEC by enclosing it in brackets,
               as in `-q[query operation]'.

               The verbose style is used to decide whether the
               explanation strings are displayed with the option in a
               completion listing.

               If no bracketed explanation string is given but the
               auto-description style is set and only one argument is
               described for this OPTSPEC, the value of the style is
               displayed, with any appearance of the sequence `%d' in
               it replaced by the MESSAGE of the first OPTARG that
               follows the OPTSPEC; see below.


          It is possible for options with a literal `+' or `=' to
          appear, but that character must be quoted, for example `-\+'.

          Each OPTARG following an OPTSPEC must take one of the
          following forms:


         :MESSAGE:ACTION
         ::MESSAGE:ACTION
               An argument to the option; MESSAGE and ACTION are
               treated as for ordinary arguments.  In the first form,
               the argument is mandatory, and in the second form it is
               optional.

               This group may be repeated for options which take
               multiple arguments.  In other words,
               :MESSAGE1:ACTION1:MESSAGE2:ACTION2 specifies that the
               option takes two arguments.

         :*PATTERN:MESSAGE:ACTION
         :*PATTERN::MESSAGE:ACTION
         :*PATTERN:::MESSAGE:ACTION
               This describes multiple arguments.  Only the last OPTARG
               for an option taking multiple arguments may be given in
               this form.  If the PATTERN is empty (i.e., :*:), all the
               remaining words on the line are to be completed as
               described by the ACTION; otherwise, all the words up to
               and including a word matching the PATTERN are to be
               completed using the ACTION.

               Multiple colons are treated as for the `*:...' forms for
               ordinary arguments:  when the MESSAGE is preceded by two
               colons, the words special array and the CURRENT special
               parameter are modified during the execution or
               evaluation of the ACTION to refer only to the words
               after the option.  When preceded by three colons, they
               are modified to refer only to the words covered by this
               description.



     Any literal colon in an OPTNAME, MESSAGE, or ACTION must be
     preceded by a backslash, `\:'.

     Each of the forms above may be preceded by a list in parentheses
     of option names and argument numbers.  If the given option is on
     the command line, the options and arguments indicated in
     parentheses will not be offered.  For example, `(-two -three
     1)-one:...' completes the option `-one'; if this appears on the
     command line, the options -two and -three and the first ordinary
     argument will not be completed after it.  `(-foo):...' specifies
     an ordinary argument completion; -foo will not be completed if
     that argument is already present.

     Other items may appear in the list of excluded options to indicate
     various other items that should not be applied when the current
     specification is matched: a single star (*) for the rest arguments
     (i.e. a specification of the form `*:...'); a colon (:) for all
     normal (non-option-) arguments; and a hyphen (-) for all options.
     For example, if `(*)' appears before an option and the option
     appears on the command line, the list of remaining arguments
     (those shown in the above table beginning with `*:') will not be
     completed.

     To aid in reuse of specifications, it is possible to precede any
     of the forms above with `!'; then the form will no longer be
     completed, although if the option or argument appears on the
     command line they will be skipped as normal.  The main use for
     this is when the arguments are given by an array, and _arguments
     is called repeatedly for more specific contexts: on the first call
     `_arguments $global_options' is used, and on subsequent calls
     `_arguments !$^global_options'.

     In each of the forms above the ACTION determines how completions
     should be generated.  Except for the `->STRING' form below, the
     ACTION will be executed by calling the _all_labels function to
     process all tag labels.  No special handling of tags is needed
     unless a function call introduces a new one.

     The forms for ACTION are as follows.


      (single unquoted space)
          This is useful where an argument is required but it is not
          possible or desirable to generate matches for it.  The
          MESSAGE will be displayed but no completions listed.  Note
          that even in this case the colon at the end of the MESSAGE is
          needed; it may only be omitted when neither a MESSAGE nor an
          ACTION is given.

    (ITEM1 ITEM2 ...)
          One of a list of possible matches, for example:


               :foo:(foo bar baz)

    ((ITEM1\:DESC1 ...))
          Similar to the above, but with descriptions for each possible
          match.  Note the backslash before the colon.  For example,


               :foo:((a\:bar b\:baz))

          The matches will be listed together with their descriptions
          if the description style is set with the values tag in the
          context.

    ->STRING
          In this form, _arguments processes the arguments and options
          and then returns control to the calling function with
          parameters set to indicate the state of processing; the
          calling function then makes its own arrangements for
          generating completions.  For example, functions that
          implement a state machine can use this type of action.

          Where _arguments encounters a `->STRING', it will strip all
          leading and trailing whitespace from STRING and set the array
          state to the set of all STRINGSs for which an action is to be
          performed.

          By default and in common with all other well behaved
          completion functions, _arguments returns status zero if it
          was able to add matches and non-zero otherwise. However, if
          the -R option is given, _arguments will instead return a
          status of 300 to indicate that $state is to be handled.

          In addition to $state, _arguments also sets the global
          parameters `context', `line' and `opt_args' as described
          below, and does not reset any changes made to the special
          parameters such as PREFIX and words.  This gives the calling
          function the choice of resetting these parameters or
          propagating changes in them.

          A function calling _arguments with at least one action
          containing a `->STRING' must therefore declare appropriate
          local parameters:


               local context state line
               typeset -A opt_args

          to prevent _arguments from altering the global environment.

    {EVAL-STRING}
          A string in braces is evaluated as shell code to generate
          matches.  If the EVAL-STRING itself does not begin with an
          opening parenthesis or brace it is split into separate words
          before execution.

    = ACTION
          If the ACTION starts with `= ' (an equals sign followed by a
          space), _arguments will insert the contents of the ARGUMENT
          field of the current context as the new first element in the
          words special array and increment the value of the CURRENT
          special parameter.  This has the effect of inserting a dummy
          word onto the completion command line while not changing the
          point at which completion is taking place.

          This is most useful with one of the specifiers that restrict
          the words on the command line on which the ACTION is to
          operate (the two- and three-colon forms above).  One
          particular use is when an ACTION itself causes _arguments on
          a restricted range; it is necessary to use this trick to
          insert an appropriate command name into the range for the
          second call to _arguments to be able to parse the line.

    WORD...
    WORD...
          This covers all forms other than those above.  If the ACTION
          starts with a space, the remaining list of words will be
          invoked unchanged.

          Otherwise it will be invoked with some extra strings placed
          after the first word; these are to be passed down as options
          to the compadd builtin.  They ensure that the state specified
          by _arguments, in particular the descriptions of options and
          arguments, is correctly passed to the completion command.
          These additional arguments are taken from the array parameter
          `expl'; this will be set up before executing the ACTION and
          hence may be referred to inside it, typically in an expansion
          of the form `$expl[@]' which preserves empty elements of the
          array.


     During the performance of the action the array `line' will be set
     to the command name and normal arguments from the command line,
     i.e. the words from the command line excluding all options and
     their arguments.  Options are stored in the associative array
     `opt_args' with option names as keys and their arguments as the
     values.  For options that have more than one argument these are
     given as one string, separated by colons.  All colons in the
     original arguments are preceded with backslashes.

     The parameter `context' is set when returning to the calling
     function to perform an action of the form `->STRING'.  It is set
     to an array of elements corresponding to the elements of $state.
     Each element is a suitable name for the argument field of the
     context: either a string of the form `option-OPT-N' for the N'th
     argument of the option -OPT, or a string of the form `argument-N'
     for the N'th argument.  For `rest' arguments, that is those in the
     list at the end not handled by position, N is the string `rest'.
     For example, when completing the argument of the -o option, the
     name is `option-o-1', while for the second normal (non-option-)
     argument it is `argument-2'.

     Furthermore, during the evaluation of the ACTION the context name
     in the curcontext parameter is altered to append the same string
     that is stored in the context parameter.

     It is possible to specify multiple sets of options and arguments
     with the sets separated by single hyphens.  The specifications
     before the first hyphen (if any) are shared by all the remaining
     sets.  The first word in every other set provides a name for the
     set which may appear in exclusion lists in specifications, either
     alone or before one of the possible values described above.  In
     the second case a `-' should appear between this name and the
     remainder.

     For example:


          _arguments \
              -a \
            - set1 \
              -c \
            - set2 \
              -d \
              ':arg:(x2 y2)'

     This defines two sets.  When the command line contains the option
     `-c', the `-d' option and the argument will not be considered
     possible completions.  When it contains `-d' or an argument, the
     option `-c' will not be considered.  However, after `-a' both sets
     will still be considered valid.

     If the name given for one of the mutually exclusive sets is of the
     form `(NAME)' then only one value from each set will ever be
     completed; more formally, all specifications are mutually
     exclusive to all other specifications in the same set.  This is
     useful for defining multiple sets of options which are mutually
     exclusive and in which the options are aliases for each other.  For
     example:


          _arguments \
              -a -b \
            - '(compress)' \
              {-c,--compress}'[compress]' \
            - '(uncompress)' \
              {-d,--decompress}'[decompress]'

     As the completion code has to parse the command line separately
     for each set this form of argument is slow and should only be used
     when necessary.  A useful alternative is often an option
     specification with rest-arguments (as in `-foo:*:...'); here the
     option -foo swallows up all remaining arguments as described by
     the OPTARG definitions.

     The options -S and -A are available to simplify the specifications
     for commands with standard option parsing.  With -S, no option
     will be completed after a `--' appearing on its own on the line;
     this argument will otherwise be ignored; hence in the line


          foobar -a -- -b

     the `-a' is considered an option but the `-b' is considered an
     argument, while the `--' is considered to be neither.

     With -A, no options will be completed after the first non-option
     argument on the line.  The -A must be followed by a pattern
     matching all strings which are not to be taken as arguments.  For
     example, to make _arguments stop completing options after the
     first normal argument, but ignoring all strings starting with a
     hyphen even if they are not described by one of the OPTSPECs, the
     form is `-A "-*"'.

     The option `-O NAME' specifies the name of an array whose elements
     will be passed as arguments to functions called to execute ACTIONS.
     For example, this can be used to pass the same set of options for
     the compadd builtin to all ACTIONs.

     The option `-M SPEC' sets a match specification to use to
     completion option names and values.  It must appear before the
     first argument specification.  The default is `r:|[_-]=* r:|=*':
     this allows partial word completion after `_' and `-', for example
     `-f-b' can be completed to `-foo-bar'.

     The option -C tells _arguments to modify the curcontext parameter
     for an action of the form `->STATE'.  This is the standard
     parameter used to keep track of the current context.  Here it (and
     not the context array) should be made local to the calling function
     to avoid passing back the modified value and should be initialised
     to the current value at the start of the function:


          local curcontext="$curcontext"

     This is useful where it is not possible for multiple states to be
     valid together.

     The option `--' allows _arguments to work out the names of long
     options that support the `--help' option which is standard in many
     GNU commands.  The command word is called with the argument
     `--help' and the output examined for option names.  Clearly, it can
     be dangerous to pass this to commands which may not support this
     option as the behaviour of the command is unspecified.

     In addition to options, `_arguments --' will try to deduce the
     types of arguments available for options when the form `--OPT=VAL'
     is valid.  It is also possible to provide hints by examining the
     help text of the command and adding specifiers of the form
     `PATTERN:MESSAGE:ACTION'; note that normal _arguments specifiers
     are not used.  The PATTERN is matched against the help text for an
     option, and if it matches the MESSAGE and ACTION are used as for
     other argument specifiers.  For example:


          _arguments -- '*\*:toggle:(yes no)' \
                        '*=FILE*:file:_files' \
                        '*=DIR*:directory:_files -/' \
                        '*=PATH*:directory:_files -/'

     Here, `yes' and `no' will be completed as the argument of options
     whose description ends in a star; file names will be completed for
     options that contain the substring `=FILE' in the description; and
     directories will be completed for options whose description
     contains `=DIR' or `=PATH'.  The last three are in fact the
     default and so need not be given explicitly, although it is
     possible to override the use of these patterns.  A typical help
     text which uses this feature is:


            -C, --directory=DIR          change to directory DIR

     so that the above specifications will cause directories to be
     completed after `--directory', though not after `-C'.

     Note also that _arguments tries to find out automatically if the
     argument for an option is optional.  This can be specified
     explicitly by doubling the colon before the MESSAGE.

     If the PATTERN ends in `(-)', this will be removed from the
     pattern and the ACTION will be used only directly after the `=',
     not in the next word.  This is the behaviour of a normal
     specification defined with the form `=-'.

     The `_arguments --' can be followed by the option `-i PATTERNS' to
     give patterns for options which are not to be completed.  The
     patterns can be given as the name of an array parameter or as a
     literal list in parentheses.  For example,


          _arguments -- -i \
              "(--(en|dis)able-FEATURE*)"

     will cause completion to ignore the options `--enable-FEATURE' and
     `--disable-FEATURE' (this example is useful with GNU configure).

     The `_arguments --' form can also be followed by the option `-s
     PAIR' to describe option aliases.  Each PAIR consists of a pattern
     and a replacement.  For example, some configure-scripts describe
     options only as `--enable-foo', but also accept `--disable-foo'.
     To allow completion of the second form:


          _arguments -- -s "(#--enable- --disable-)"

     Here is a more general example of the use of _arguments:


          _arguments '-l+:left border:' \
                     '-format:paper size:(letter A4)' \
                     '*-copy:output file:_files::resolution:(300 600)' \
                     ':postscript file:_files -g \*.\(ps\|eps\)' \
                     '*:page number:'

     This describes three options: `-l', `-format', and `-copy'.  The
     first takes one argument described as `LEFT BORDER' for which no
     completion will be offered because of the empty action.  Its
     argument may come directly after the `-l' or it may be given as
     the next word on the line.

     The `-format' option takes one argument in the next word,
     described as `PAPER SIZE' for which only the strings `letter' and
     `A4' will be completed.

     The `-copy' option may appear more than once on the command line
     and takes two arguments.  The first is mandatory and will be
     completed as a filename.  The second is optional (because of the
     second colon before the description `RESOLUTION') and will be
     completed from the strings `300' and `600'.

     The last two descriptions say what should be completed as
     arguments.  The first describes the first argument as a
     `POSTSCRIPT FILE' and makes files ending in `ps' or `eps' be
     completed.  The last description gives all other arguments the
     description `PAGE NUMBERS' but does not offer completions.

_cache_invalid CACHE_IDENTIFIER
     This function returns status zero if the completions cache
     corresponding to the given cache identifier needs rebuilding.  It
     determines this by looking up the cache-policy style for the
     current context.  This should provide a function name which is run
     with the full path to the relevant cache file as the only argument.

     Example:


          _example_caching_policy () {
              # rebuild if cache is more than a week old
              local -a oldp
              oldp=( "$1"(Nmw+1) )
              (( $#oldp ))
          }

_call_function RETURN NAME [ ARGS ... ]
     If a function NAME exists, it is called with the arguments ARGS.
     The RETURN argument gives the name of a parameter in which the
     return status from the function NAME should be stored; if RETURN
     is empty or a single hyphen it is ignored.

     The return status of _call_function itself is zero if the function
     NAME exists and was called and non-zero otherwise.

_call_program TAG STRING ...
     This function provides a mechanism for the user to override the
     use of an external command.  It looks up the command style with
     the supplied TAG.  If the style is set, its value is used as the
     command to execute.  The STRINGs from the call to _call_program,
     or from the style if set, are concatenated with spaces between
     them and the resulting string is evaluated.  The return status is
     the return status of the command called.

_combination [ -s PATTERN ] TAG STYLE SPEC ... FIELD OPTS ...
     This function is used to complete combinations of values,  for
     example pairs of hostnames and usernames.  The STYLE argument
     gives the style which defines the pairs; it is looked up in a
     context with the TAG specified.

     The style name consists of field names separated by hyphens, for
     example `users-hosts-ports'.  For each field for a value is
     already known, a SPEC of the form `FIELD=PATTERN' is given.  For
     example, if the command line so far specifies a user `pws', the
     argument `users=pws' should appear.

     The next argument with no equals sign is taken as the name of the
     field for which completions should be generated (presumably not
     one of the FIELDs for which the value is known).

     The matches generated will be taken from the value of the style.
     These should contain the possible values for the combinations in
     the appropriate order (users, hosts, ports in the example above).
     The different fields the values for the different fields are
     separated by colons.  This can be altered with the option -s to
     _combination which specifies a pattern.  Typically this is a
     character class, as for example `-s "[:@]"' in the case of the
     users-hosts style.    Each `FIELD=PATTERN' specification restricts
     the completions which apply to elements of the style with
     appropriately matching fields.

     If no style with the given name is defined for the given tag, or
     if none of the strings in style's value match, but a function name
     of the required field preceded by an underscore is defined, that
     function will be called to generate the matches.  For example, if
     there is no `users-hosts-ports' or no matching hostname when a
     host is required, the function `_hosts' will automatically be
     called.

     If the same name is used for more than one field, in both the
     `FIELD=PATTERN' and the argument that gives the name of the field
     to be completed, the number of the field (starting with one) may
     be given after the fieldname, separated from it by a colon.

     All arguments after the required field name are passed to compadd
     when generating matches from the style value, or to the functions
     for the fields if they are called.

_describe [ -oO | -t TAG ] DESCR NAME1 [ NAME2 ] OPTS ... -- ...
     This function associates completions with descriptions.  Multiple
     groups separated by -- can be supplied, potentially with different
     completion options OPTS.

     The DESCR is taken as a string to display above the matches if the
     format style for the descriptions tag is set.  This is followed by
     one or two names of arrays followed by options to pass to compadd.
     The first array contains the possible completions with their
     descriptions in the form `COMPLETION:DESCRIPTION'.  Any literal
     colons in COMPLETION must be quoted with a backslash.  If a second
     array is given, it should have the same number of elements as the
     first; in this case the corresponding elements are added as
     possible completions instead of the COMPLETION strings from the
     first array.  The completion list will retain the descriptions
     from the first array.  Finally, a set of completion options can
     appear.

     If the option `-o' appears before the first argument, the matches
     added will be treated as names of command options (N.B. not shell
     options), typically following a `-', `--' or `+' on the command
     line.  In this case _describe uses the prefix-hidden,
     prefix-needed and verbose styles to find out if the strings should
     be added as completions and if the descriptions should be shown.
     Without the `-o' option, only the verbose style is used to decide
     how descriptions are shown.  If `-O' is used instead of `-o',
     command options are completed as above but _describe will not
     handle the prefix-needed style.

     With the -t option a TAG can be specified.  The default is
     `values' or, if the -o option is given, `options'.

     If selected by the list-grouped style, strings with the same
     description will appear together in the list.

     _describe uses the _all_labels function to generate the matches, so
     it does not need to appear inside a loop over tag labels.

_description [ -x ] [ -12VJ ] TAG NAME DESCR [ SPEC ... ]
     This function is not to be confused with the previous one; it is
     used as a helper function for creating options to compadd.  It is
     buried inside many of the higher level completion functions and so
     often does not need to be called directly.

     The styles listed below are tested in the current context using the
     given TAG.  The resulting options for compadd are put into the
     array named NAME (this is traditionally `expl', but this
     convention is not enforced).  The description for the
     corresponding set of matches is passed to the function in DESCR.

     The styles tested are: format, hidden, matcher, ignored-patterns
     and group-name.  The format style is first tested for the given
     TAG and then for the descriptions tag if no value was found, while
     the remainder are only tested for the tag given as the first
     argument.  The function also calls _setup which tests some more
     styles.

     The string returned by the format style (if any) will be modified
     so that the sequence `%d' is replaced by the DESCR given as the
     third argument without any leading or trailing white space.  If,
     after removing the white space, the DESCR is the empty string, the
     format style will not be used and the options put into the NAME
     array will not contain an explanation string to be displayed above
     the matches.

     If _description is called with more than three arguments, the
     additional SPECs should be of the form `CHAR:STR'.  These supply
     escape sequence replacements for the format style: every
     appearance of `%CHAR' will be replaced by STRING.

     If the -x option is given, the description will be passed to
     compadd using the -x option instead of the default -X.  This means
     that the description will be displayed even if there are no
     corresponding matches.

     The options placed in the array NAME take account of the
     group-name style, so matches are placed in a separate group where
     necessary.  The group normally has its elements sorted (by passing
     the option -J to compadd), but if an option starting with `-V',
     `-J', `-1', or `-2' is passed to _description, that option will be
     included in the array.  Hence it is possible for the completion
     group to be unsorted by giving the option `-V', `-1V', or `-2V'.

     In most cases, the function will be used like this:


          local expl
          _description files expl file
          compadd "$expl[@]" - "$files[@]"

     Note the use of the parameter expl, the hyphen, and the list of
     matches.  Almost all calls to compadd within the completion system
     use a similar format; this ensures that user-specified styles are
     correctly passed down to the builtins which implement the
     internals of completion.

_dispatch CONTEXT STRING ...
     This sets the current context to CONTEXT and looks for completion
     functions to handle this context by hunting through the list of
     command names or special contexts (as described above for compdef)
     given as STRING ....  The first completion function to be defined
     for one of the contexts in the list is used to generate matches.
     Typically, the last STRING is -default- to cause the function for
     default completion to be used as a fallback.

     The function sets the parameter $service to the STRING being
     tried, and sets the CONTEXT/COMMAND field (the fourth) of the
     $curcontext parameter to the CONTEXT given as the first argument.

_files
     The function _files calls _path_files with all the arguments it
     was passed except for -g and -/.  The use of these two options
     depends on the setting of the  file-patterns style.

     This function accepts the full set of options allowed by
     _path_files, described below.

_gnu_generic
     This function is a simple wrapper around the _arguments function
     described above.  It can be used to determine automatically the
     long options understood by commands that produce a list when
     passed the option `--help'.  It is intended to be used as a
     top-level completion function in its own right.  For example, to
     enable option completion for the commands foo and bar, use


          compdef _gnu_generic foo bar

     after the call to compinit.

     The completion system as supplied is conservative in its use of
     this function, since it is important to be sure the command
     understands the option `--help'.

_guard [ OPTIONS ] PATTERN DESCR
     This function is intended to be used in the ACTION for the
     specifications passed to _arguments and similar functions.  It
     returns immediately with a non-zero return status if the string to
     be completed does not match the PATTERN.  If the pattern matches,
     the DESCR is displayed; the function then returns status zero if
     the word to complete is not empty, non-zero otherwise.

     The PATTERN may be preceded by any of the options understood by
     compadd that are passed down from _description, namely -M, -J, -V,
     -1, -2, -n, -F and -X.  All of these options will be ignored.
     This fits in conveniently with the argument-passing conventions of
     actions for _arguments.

     As an example, consider a command taking the options -n and -none,
     where -n must be followed by a numeric value in the same word.  By
     using:


          _arguments '-n-: :_guard "[0-9]#" "numeric value"' '-none'

     _arguments can be made to both display the message `numeric value'
     and complete options after `-n<TAB>'.  If the `-n' is already
     followed by one or more digits (the pattern passed to _guard) only
     the message will be displayed; if the `-n' is followed by another
     character, only options are completed.

_message [ -r12 ] [ -VJ GROUP ] DESCR
_message -e [ TAG ] DESCR
     The DESCR is used in the same way as the third argument to the
     _description function, except that the resulting string will
     always be shown whether or not matches were generated.  This is
     useful for displaying a help message in places where no
     completions can be generated.

     The format style is examined with the messages tag to find a
     message; the usual tag, descriptions, is used only if the style is
     not set with the former.

     If the -r option is given, no style is used; the DESCR is taken
     literally as the string to display.  This is most useful when the
     DESCR comes from a pre-processed argument list which already
     contains an expanded description.

     The -12VJ options and the GROUP are passed to compadd and hence
     determine the group the message string is added to.

     The second form gives a description for completions with the tag
     TAG to be shown even if there are no matches for that tag.  The tag
     can be omitted and if so the tag is taken from the parameter
     $curtag; this is maintained by the completion system and so is
     usually correct.

_multi_parts SEP ARRAY
     The argument SEP is a separator character.  The ARRAY may be
     either the name of an array parameter or a literal array in the
     form `(foo bar)', a parenthesised list of words separated by
     whitespace.  The possible completions are the strings from the
     array.  However, each chunk delimited by SEP will be completed
     separately.  For example, the _tar function uses `_multi_parts /
     PATHARRAY' to complete partial file paths from the given array of
     complete file paths.

     The -i option causes _multi_parts to insert a unique match even if
     that requires multiple separators to be inserted.  This is not
     usually the expected behaviour with filenames, but certain other
     types of completion, for example those with a fixed set of
     possibilities, may be more suited to this form.

     Like other utility functions, this function accepts the `-V',
     `-J', `-1', `-2', `-n', `-f', `-X', `-M', `-P', `-S', `-r', `-R',
     and `-q' options and passes them to the compadd builtin.

_next_label [ -x ] [ -12VJ ] TAG NAME DESCR [ OPTIONS ... ]
     This function is used to implement the loop over different tag
     labels for a particular tag as described above for the tag-order
     style.  On each call it checks to see if there are any more tag
     labels; if there is it returns status zero, otherwise non-zero.
     As this function requires a current tag to be set, it must always
     follow a call to _tags or _requested.

     The -x12VJ options and the first three arguments are passed to the
     _description function.  Where appropriate the TAG will be replaced
     by a tag label in this call.  Any description given in the
     tag-order style is preferred to the DESCR passed to _next_label.

     The OPTIONS given after the DESCR are set in the parameter given
     by NAME, and hence are to be passed to compadd or whatever
     function is called to add the matches.

     Here is a typical use of this function for the tag foo.  The call
     to _requested determines if tag foo is required at all; the loop
     over _next_label handles any labels defined for the tag in the
     tag-order style.


          local expl ret=1
          ...
          if _requested foo; then
            ...
            while _next_label foo expl '...'; do
              compadd "$expl[@]" ... && ret=0
            done
            ...
          fi
          return ret

_normal
     This is the standard function called to handle completion outside
     any special -CONTEXT-.  It is called both to complete the command
     word and also the arguments for a command.  In the second case,
     _normal looks for a special completion for that command, and if
     there is none it uses the completion for the -default- context.

     A second use is to reexamine the command line specified by the
     $words array and the $CURRENT parameter after those have been
     modified.  For example, the function _precommand, which completes
     after pre-command specifiers such as nohup, removes the first word
     from the words array, decrements the CURRENT parameter, then calls
     _normal again.  The effect is that `nohup CMD ...'  is treated in
     the same way as `CMD ...'.

     If the command name matches one of the patterns given by one of the
     options -p or -P to compdef, the corresponding completion function
     is called and then the parameter _compskip is checked.  If it is
     set completion is terminated at that point even if no matches have
     been found.  This is the same effect as in the -first- context.

_options
     This can be used to complete the names of shell options.  It
     provides a matcher specification that ignores a leading `no',
     ignores underscores and allows upper-case letters to match their
     lower-case counterparts (for example, `glob', `noglob', `NO_GLOB'
     are all completed).  Any arguments are propagated to the compadd
     builtin.

_options_set and _options_unset
     These functions complete only set or unset options, with the same
     matching specification used in the _options function.

     Note that you need to uncomment a few lines in the _main_complete
     function for these functions to work properly.  The lines in
     question are used to store the option settings in effect before
     the completion widget locally sets the options it needs.  Hence
     these functions are not generally used by the completion system.

_parameters
     This is used to complete the names of shell parameters.

     The option `-g PATTERN' limits the completion to parameters whose
     type matches the PATTERN.  The type of a parameter is that shown
     by `print ${(t)PARAM}', hence judicious use of `*' in PATTERN is
     probably necessary.

     All other arguments are passed to the compadd builtin.

_path_files
     This function is used throughout the completion system to complete
     filenames.  It allows completion of partial paths.  For example,
     the string `/u/i/s/sig' may be completed to
     `/usr/include/sys/signal.h'.

     The options accepted by both _path_files and _files are:


    -f
          Complete all filenames.  This is the default.

    -/
          Specifies that only directories should be completed.

    -g PATTERN
          Specifies that only files matching the PATTERN should be
          completed.

    -W PATHS
          Specifies path prefixes that are to be prepended to the
          string from the command line to generate the filenames but
          that should not be inserted as completions nor shown in
          completion listings.  Here, PATHS may be the name of an array
          parameter, a literal list of paths enclosed in parentheses or
          an absolute pathname.

    -F IGNORED-FILES
          This behaves as for the corresponding option to the compadd
          builtin.  It gives direct control over which filenames should
          be ignored.  If the option is not present, the
          ignored-patterns style is used.


     Both _path_files and _files also accept the following options
     which are passed to compadd: `-J', `-V', `-1', `-2', `-n', `-X',
     `-M', `-P', `-S', `-q', `-r', and `-R'.

     Finally, the _path_files function  uses the styles expand,
     ambiguous, special-dirs, list-suffixes and file-sort described
     above.

_pick_variant [ -c COMMAND ] [ -r NAME ] LABEL=PATTERN ... LABEL [ ARGS ... ]
     This function is used to resolve situations where a single command
     name requires more than one type of handling, either because it
     has more than one variant or because there is a name clash between
     two different commands.

     The command to run is taken from the first element of the array
     words unless this is overridden by the option -c.  This command is
     run and its output is compared with a series of patterns.
     Arguments to be passed to the command can be specified at the end
     after all the other arguments.  The patterns to try in order are
     given by the arguments LABEL=PATTERN; if the output of `COMMAND
     ARGS ...' contains PATTERN, then label is selected as the label
     for the command variant.  If none of the patterns match, the final
     command label is selected and status 1 is returned.

     If the `-r NAME' is given, the LABEL picked is stored in the
     parameter named NAME.

     The results are also cached in the _CMD_VARIANT associative array
     indexed by the name of the command run.

_regex_arguments NAME SPEC ...
     This function generates a completion function NAME which matches
     the specifications SPEC ..., a set of regular expressions as
     described below.  After running _regex_arguments, the function
     NAME should be called as a normal completion function.  The
     pattern to be matched is given by the contents of the words array
     up to the current cursor position joined together with null
     characters; no quotation is applied.

     The arguments are grouped as sets of alternatives separated by `|',
     which are tried one after the other until one matches.  Each
     alternative consists of a one or more specifications which are
     tried left to right, with each pattern matched being stripped in
     turn from the command line being tested, until all of the group
     succeeds or until one fails; in the latter case, the next
     alternative is tried.  This structure can be repeated to arbitrary
     depth by using parentheses; matching proceeds from inside to
     outside.

     A special procedure is applied if no test succeeds but the
     remaining command line string contains no null character (implying
     the remaining word is the one for which completions are to be
     generated).  The completion target is restricted to the remaining
     word and any ACTIONs for the corresponding patterns are executed.
     In this case, nothing is stripped from the command line string.
     The order of evaluation of the ACTIONs can be determined by the
     tag-order style; the various formats supported by _alternative can
     be used in ACTION.  The DESCR is used for setting up the array
     parameter expl.

     Specification arguments take one of following forms, in which
     metacharacters such as `(', `)', `#' and `|' should be quoted.


    /PATTERN/ [%LOOKAHEAD%] [-GUARD] [:TAG:DESCR:ACTION]
          This is a single primitive component.  The function tests
          whether the combined pattern `(#b)((#B)PATTERN)LOOKAHEAD*'
          matches the command line string.  If so, `GUARD' is evaluated
          and its return status is examined to determine if the test
          has succeeded.  The PATTERN string `[]' is guaranteed never
          to match.  The LOOKAHEAD is not stripped from the command
          line before the next pattern is examined.

          The argument starting with : is used in the same manner as an
          argument to _alternative.

          A component is used as follows: PATTERN is tested to see if
          the component already exists on the command line.  If it
          does, any following specifications are examined to find
          something to complete.  If a component is reached but no such
          pattern exists yet on the command line, the string containing
          the ACTION is used to generate matches to insert at that
          point.

    /PATTERN/+ [%LOOKAHEAD%] [-GUARD] [:TAG:DESCR:ACTION]
          This is similar to `/PATTERN/ ...' but the left part of the
          command line string (i.e. the part already matched by
          previous patterns) is also considered part of the completion
          target.

    /PATTERN/- [%LOOKAHEAD%] [-GUARD] [:TAG:DESCR:ACTION]
          This is similar to `/PATTERN/ ...' but the ACTIONs of the
          current and previously matched patterns are ignored even if
          the following `PATTERN' matches the empty string.

    ( SPEC )
          Parentheses may be used to groups SPECs; note each parenthesis
          is a single argument to _regex_arguments.

    SPEC #
          This allows any number of repetitions of SPEC.

    SPEC SPEC
          The two SPECs are to be matched one after the other as
          described above.

    SPEC | SPEC
          Either of the two SPECs can be matched.


     The function _regex_words can be used as a helper function to
     generate matches for a set of alternative words possibly with
     their own arguments as a command line argument.

     Examples:


          _regex_arguments _tst /$'[^\0]#\0'/ \
          /$'[^\0]#\0'/ :'compadd aaa'

     This generates a function _tst that completes aaa as its only
     argument.  The TAG and DESCRIPTION for the action have been
     omitted for brevity (this works but is not recommended in normal
     use).  The first component matches the command word, which is
     arbitrary; the second matches  any argument.  As the argument is
     also arbitrary, any following component would not depend on aaa
     being present.


          _regex_arguments _tst /$'[^\0]#\0'/ \
          /$'aaa\0'/ :'compadd aaa'

     This is a more typical use; it is similar, but any following
     patterns would only match if aaa was present as the first argument.


          _regex_arguments _tst /$'[^\0]#\0'/ \( \
          /$'aaa\0'/ :'compadd aaa' \
          /$'bbb\0'/ :'compadd bbb' \) \#

     In this example, an indefinite number of command arguments may be
     completed.  Odd arguments are completed as aaa and even arguments
     as bbb.  Completion fails unless the set of aaa and bbb arguments
     before the current one is matched correctly.


          _regex_arguments _tst /$'[^\0]#\0'/ \
          \( /$'aaa\0'/ :'compadd aaa' \| \
          /$'bbb\0'/ :'compadd bbb' \) \#

     This is similar, but either aaa or bbb may be completed for any
     argument.  In this case _regex_words could be used to generate a
     suitable expression for the arguments.



_regex_words TAG DESCRIPTION SPEC ...
     This function can be used to generate arguments for the
     _regex_arguments command which may be inserted at any point where
     a set of rules is expected.  The TAG and DESCRIPTION give a
     standard tag and description pertaining to the current context.
     Each SPEC contains two or three arguments separated by a colon:
     note that there is no leading colon in this case.

     Each SPEC gives one of a set of words that may be completed at
     this point, together with arguments.  It is thus roughly
     equivalent to the _arguments function when used in normal
     (non-regex) completion.

     The part of the SPEC before the first colon is the word to be
     completed.  This may contain a *; the entire word, before and after
     the * is completed, but only the text before the * is required for
     the context to be matched, so that further arguments may be
     completed after the abbreviated form.

     The second part of SPEC is a description for the word being
     completed.

     The optional third part of the SPEC describes how words following
     the one being completed are themselves to be completed.  It will be
     evaluated in order to avoid problems with quoting.  This means that
     typically it contains a reference to an array containing previously
     generated regex arguments.

     The option -t TERM specifies a terminator for the word instead of
     the usual space.  This is handled as an auto-removable suffix in
     the manner of the option -s SEP to _values.

     The result of the processing by _regex_words is placed in the array
     reply, which should be made local to the calling function.  If the
     set of words and arguments may be matched repeatedly, a # should
     be appended to the generated array at that point.

     For example:


          local -a reply
          _regex_words mydb-commands 'mydb commands' \
            'add:add an entry to mydb:$mydb_add_cmds' \
            'show:show entries in mydb'
          _regex_arguments _mydb "$reply[@]"
          _mydb "$@"

     This shows a completion function for a command mydb which takes
     two command arguments, add and show.  show takes no arguments,
     while the arguments for add have already been prepared in an array
     mydb_add_cmds, quite possibly by a previous call to _regex_words.

_requested [ -x ] [ -12VJ ] TAG [ NAME DESCR [ COMMAND ARGS ... ] ]
     This function is called to decide whether a tag already registered
     by a call to _tags (see below) has been requested by the user and
     hence completion should be performed for it.  It returns status
     zero if the tag is requested and non-zero otherwise.  The function
     is typically used as part of a loop over different tags as follows:


          _tags foo bar baz
          while _tags; do
            if _requested foo; then
              ... # perform completion for foo
            fi
            ... # test the tags bar and baz in the same way
            ... # exit loop if matches were generated
          done

     Note that the test for whether matches were generated is not
     performed until the end of the _tags loop.  This is so that the
     user can set the tag-order style to specify a set of tags to be
     completed at the same time.

     If NAME and DESCR are given, _requested calls the _description
     function with these arguments together with the options passed to
     _requested.

     If COMMAND is given, the _all_labels function will be called
     immediately with the same arguments.  In simple cases this makes it
     possible to perform the test for the tag and the matching in one
     go.  For example:


          local expl ret=1
          _tags foo bar baz
          while _tags; do
            _requested foo expl 'description' \
                compadd foobar foobaz && ret=0
            ...
            (( ret )) || break
          done

     If the COMMAND is not compadd, it must nevertheless be prepared to
     handle the same options.

_retrieve_cache CACHE_IDENTIFIER
     This function retrieves completion information from the file given
     by CACHE_IDENTIFIER, stored in a directory specified by the
     cache-path style which defaults to ~/.zcompcache.  The return
     status is zero if retrieval was successful.  It will only attempt
     retrieval if the use-cache style is set, so you can call this
     function without worrying about whether the user wanted to use the
     caching layer.

     See _store_cache below for more details.

_sep_parts
     This function is passed alternating arrays and separators as
     arguments.  The arrays specify completions for parts of strings to
     be separated by the separators.  The arrays may be the names of
     array parameters or a quoted list of words in parentheses.  For
     example, with the array `hosts=(ftp news)' the call `_sep_parts
     '(foo bar)' @ hosts' will complete the string  `f' to `foo' and
     the string `b@n' to `bar@news'.

     This function accepts the compadd options `-V', `-J', `-1', `-2',
     `-n', `-X', `-M', `-P', `-S', `-r', `-R', and `-q' and passes them
     on to the compadd builtin used to add the matches.

_setup TAG [ GROUP ]
     This function sets up the special parameters used by the
     completion system appropriately for the TAG given as the first
     argument.  It uses the styles list-colors, list-packed,
     list-rows-first, last-prompt, accept-exact, menu and force-list.

     The optional GROUP supplies the name of the group in which the
     matches will be placed.  If it is not given, the TAG is used as
     the group name.

     This function is called automatically from _description and hence
     is not normally called explicitly.

_store_cache CACHE_IDENTIFIER PARAMS ...
     This function, together with _retrieve_cache and _cache_invalid,
     implements a caching layer which can be used in any completion
     function.  Data obtained by costly operations are stored in
     parameters; this function then dumps the values of those
     parameters to a file.  The data can then be retrieved quickly from
     that file via _retrieve_cache, even in different instances of the
     shell.

     The CACHE_IDENTIFIER specifies the file which the data should be
     dumped to.  The file is stored in a directory specified by the
     cache-path style which defaults to ~/.zcompcache.  The remaining
     PARAMS arguments are the parameters to dump to the file.

     The return status is zero if storage was successful.  The function
     will only attempt storage if the use-cache style is set, so you can
     call this function without worrying about whether the user wanted
     to use the caching layer.

     The completion function may avoid calling _retrieve_cache when it
     already has the completion data available as parameters.  However,
     in that case it should call _cache_invalid to check whether the
     data in the parameters and in the cache are still valid.

     See the _perl_modules completion function for a simple example of
     the usage of the caching layer.

_tags [ [ -C NAME ] TAGS ... ]
     If called with arguments, these are taken to be the names of tags
     valid for completions in the current context.  These tags are
     stored internally and sorted by using the tag-order style.

     Next, _tags is called repeatedly without arguments from the same
     completion function.  This successively selects the first, second,
     etc. set of tags requested by the user.  The return status is zero
     if at least one of the tags is requested and non-zero otherwise.
     To test if a particular tag is to be tried, the _requested
     function should be called (see above).

     If `-C NAME' is given, NAME is temporarily stored in the argument
     field (the fifth) of the context in the curcontext parameter
     during the call to _tags; the field is restored on exit.  This
     allows _tags to use a more specific context without having to
     change and reset the curcontext parameter (which has the same
     effect).

_values [ -O NAME ] [ -s SEP ] [ -S SEP ] [ -wC ] DESC SPEC ...
     This is used to complete arbitrary keywords (values) and their
     arguments, or lists of such combinations.

     If the first argument is the option `-O NAME', it will be used in
     the same way as by the _arguments function.  In other words, the
     elements of the NAME array will be passed to compadd when
     executing an action.

     If the first argument (or the first argument after `-O NAME') is
     `-s', the next argument is used as the character that separates
     multiple values.  This character is automatically added after each
     value in an auto-removable fashion (see below); all values
     completed by `_values -s' appear in the same word on the command
     line, unlike completion using _arguments.  If this option is not
     present, only a single value will be completed per word.

     Normally, _values will only use the current word to determine
     which values are already present on the command line and hence are
     not to be completed again.  If the -w option is given, other
     arguments are examined as well.

     The first non-option argument is used as a string to print as a
     description before listing the values.

     All other arguments describe the possible values and their
     arguments in the same format used for the description of options by
     the _arguments function (see above).  The only differences are that
     no minus or plus sign is required at the beginning, values can
     have only one argument, and the forms of action beginning with an
     equal sign are not supported.

     The character separating a value from its argument can be set
     using the option -S (like -s, followed by the character to use as
     the separator in the next argument).  By default the equals sign
     will be used as the separator between values and arguments.

     Example:


          _values -s , 'description' \
                  '*foo[bar]' \
                  '(two)*one[number]:first count:' \
                  'two[another number]::second count:(1 2 3)'

     This describes three possible values: `foo', `one', and `two'.
     The first is described as `bar', takes no argument and may appear
     more than once.  The second is described as `number', may appear
     more than once, and takes one mandatory argument described as
     `first count'; no action is specified, so it will not be
     completed.  The `(two)' at the beginning says that if the value
     `one' is on the line, the value `two' will no longer be considered
     a possible completion.  Finally, the last value (`two') is
     described as `another number' and takes an optional argument
     described as `second count' for which the completions (to appear
     after an `=') are `1', `2', and `3'.  The _values function will
     complete lists of these values separated by commas.

     Like _arguments, this function temporarily adds another context
     name component to the arguments element (the fifth) of the current
     context while executing the ACTION.  Here this name is just the
     name of the value for which the argument is completed.

     The style verbose is used to decide if the descriptions for the
     values (but not those for the arguments) should be printed.

     The associative array val_args is used to report values and their
     arguments; this works similarly to the opt_args associative array
     used by _arguments.  Hence the function calling _values should
     declare the local parameters state, line, context and val_args:


          local context state line
          typeset -A val_args

     when using an action of the form `->STRING'.  With this function
     the context parameter will be set to the name of the value whose
     argument is to be completed.

     Note also that _values normally adds the character used as the
     separator between values as an auto-removable suffix (similar to a
     `/' after a directory).  However, this is not possible for a
     `->STRING' action as the matches for the argument are generated by
     the calling function.  To get the usual behaviour, the the calling
     function can add the separator X as a suffix by passing the
     options `-qS X' either directly or indirectly to compadd.

     The option -C is treated in the same way as it is by _arguments.
     In that case the parameter curcontext should be made local instead
     of context (as described above).

_wanted [ -x ] [ -C NAME ]  [ -12VJ ] TAG NAME DESCR COMMAND ARGS ...
     In many contexts, completion can only generate one particular set
     of matches, usually corresponding to a single tag.  However, it is
     still necessary to decide whether the user requires matches of
     this type.  This function is useful in such a case.

     The arguments to _wanted are the same as those to _requested, i.e.
     arguments to be passed to _description.  However, in this case the
     COMMAND is not optional;  all the processing of tags, including
     the loop over both tags and tag labels and the generation of
     matches, is carried out automatically by _wanted.

     Hence to offer only one tag and immediately add the corresponding
     matches with the given description:


          local expl
          _wanted tag expl 'description' \
              compadd matches...

     Note that, as for _requested, the COMMAND must be able to accept
     options to be passed down to compadd.

     Like _tags this function supports the -C option to give a
     different name for the argument context field.  The -x option has
     the same meaning as for _description.



File: zsh.info,  Node: Completion Directories,  Prev: Completion Functions,  Up: Completion System

20.7 Completion Directories
===========================



In the source distribution, the files are contained in various
subdirectories of the Completion directory.  They may have been
installed in the same structure, or into one single function directory.
The following is a description of the files found in the original
directory structure.  If you wish to alter an installed file, you will
need to copy it to some directory which appears earlier in your fpath
than the standard directory where it appears.


Base
     The core functions and special completion widgets automatically
     bound to keys.  You will certainly need most of these, though will
     probably not need to alter them.  Many of these are documented
     above.

Zsh
     Functions for completing arguments of shell builtin commands and
     utility functions for this.  Some of these are also used by
     functions from the Unix directory.

Unix
     Functions for completing arguments of external commands and suites
     of commands.  They may need modifying for your system, although in
     many cases some attempt is made to decide which version of a
     command is present.  For example, completion for the mount command
     tries to determine the system it is running on, while completion
     for many other utilities try to decide whether the GNU version of
     the command is in use, and hence whether the --help option is
     supported.

X, AIX, BSD, ...
     Completion and utility function for commands available only on
     some systems.  These are not arranged hierarchically, so, for
     example, both the Linux and Debian directories, as well as the X
     directory, may be useful on your system.


File: zsh.info,  Node: Completion Using compctl,  Next: Zsh Modules,  Prev: Completion System,  Up: Top

21 Completion Using compctl
***************************



21.1 Types of completion
========================

This version of zsh has two ways of performing completion of words on
the command line.  New users of the shell may prefer to use the newer
and more powerful system based on shell functions; this is described in
*note Completion System::, and the basic shell mechanisms which support
it are described in *note Completion Widgets::.  This chapter describes
the older compctl command.

21.2 Description
================


compctl [ -CDT ] OPTIONS [ COMMAND ... ]

compctl [ -CDT ] OPTIONS [ -x PATTERN OPTIONS - ... -- ] [ + OPTIONS [ -x ... -- ] ... [+] ] [ COMMAND ... ]

compctl -M MATCH-SPECS ...

compctl -L [ -CDTM ] [ COMMAND ... ]

compctl + COMMAND ...


Control the editor's completion behavior according to the supplied set
of OPTIONS.  Various editing commands, notably expand-or-complete-word,
usually bound to tab, will attempt to complete a word typed by the
user, while others, notably delete-char-or-list, usually bound to ^D in
EMACS editing mode, list the possibilities; compctl controls what those
possibilities are.  They may for example be filenames (the most common
case, and hence the default), shell variables, or words from a
user-specified list.

* Menu:

* Command Flags::
* Option Flags::
* Alternative Completion::
* Extended Completion::
* Example::


File: zsh.info,  Node: Command Flags,  Next: Option Flags,  Up: Completion Using compctl

21.3 Command Flags
==================

Completion of the arguments of a command may be different for each
command or may use the default.  The behavior when completing the
command word itself may also be separately specified.  These correspond
to the following flags and arguments, all of which (except for -L) may
be combined with any combination of the OPTIONS described subsequently
in *note Option Flags:::


COMMAND ...
     controls completion for the named commands, which must be listed
     last on the command line.  If completion is attempted for a
     command with a pathname containing slashes and no completion
     definition is found, the search is retried with the last pathname
     component. If the command starts with a =, completion is tried
     with the pathname of the command.

     Any of the COMMAND strings may be patterns of the form normally
     used for filename generation.  These should be be quoted to
     protect them from immediate expansion; for example the command
     string 'foo*' arranges for completion of the words of any command
     beginning with foo.  When completion is attempted, all pattern
     completions are tried in the reverse order of their definition
     until one matches.  By default, completion then proceeds as
     normal, i.e. the shell will try to generate more matches for the
     specific command on the command line; this can be overridden by
     including -tn in the flags for the pattern completion.

     Note that aliases are expanded before the command name is
     determined unless the COMPLETE_ALIASES option is set.  Commands
     may not be combined with the -C, -D or -T flags.

-C
     controls completion when the command word itself is being
     completed.  If no compctl -C command has been issued,  the names
     of any executable command (whether in the path or specific to the
     shell, such as aliases or functions) are completed.

-D
     controls default completion behavior for the arguments of commands
     not assigned any special behavior.  If no compctl -D command has
     been issued, filenames are completed.

-T
     supplies completion flags to be used before any other processing is
     done, even before processing for compctls defined for specific
     commands.  This is especially useful when combined with extended
     completion (the -x flag, see *note Extended Completion:: below).
     Using this flag you can define default behavior which will apply
     to all commands without exception, or you can alter the standard
     behavior for all commands.  For example, if your access to the
     user database is too slow and/or it contains too many users (so
     that completion after `~' is too slow to be usable), you can use


          compctl -T -x 's[~] C[0,[^/]#]' -k friends -S/ -tn

     to complete the strings in the array friends after a `~'.  The
     C[...] argument is necessary so that this form of ~-completion is
     not tried after the directory name is finished.

-L
     lists the existing completion behavior in a manner suitable for
     putting into a start-up script; the existing behavior is not
     changed.  Any combination of the above forms, or the -M flag
     (which must follow the -L flag), may be specified, otherwise all
     defined completions are listed.  Any other flags supplied are
     ignored.

_no argument_
     If no argument is given, compctl lists all defined completions in
     an abbreviated form;  with a list of OPTIONS, all completions with
     those flags set (not counting extended completion) are listed.


If the + flag is alone and followed immediately by the COMMAND list,
the completion behavior for all the commands in the list is reset to
the default.  In other words, completion will subsequently use the
options specified by the -D flag.

The form with -M as the first and only option defines global matching
specifications (see *note Completion Matching Control::). The match
specifications given will be used for every completion attempt (only
when using compctl, not with the new completion system) and are tried
in the order in which they are defined until one generates at least one
match. E.g.:


     compctl -M '' 'm:{a-zA-Z}={A-Za-z}'

This will first try completion without any global match specifications
(the empty string) and, if that generates no matches, will try case
insensitive completion.



File: zsh.info,  Node: Option Flags,  Next: Alternative Completion,  Prev: Command Flags,  Up: Completion Using compctl

21.4 Option Flags
=================


[ -fcFBdeaRGovNAIOPZEnbjrzu/12 ]

[ -k ARRAY ] [ -g GLOBSTRING ] [ -s SUBSTSTRING ]

[ -K FUNCTION ]

[ -Q ] [ -P PREFIX ] [ -S SUFFIX ]

[ -W FILE-PREFIX ] [ -H NUM PATTERN ]

[ -q ] [ -X EXPLANATION ] [ -Y EXPLANATION ]

[ -y FUNC-OR-VAR ] [ -l CMD ] [ -h CMD ] [ -U ]

[ -t CONTINUE ] [ -J NAME ] [ -V NAME ]

[ -M MATCH-SPEC ]


The remaining OPTIONS specify the type of command arguments to look for
during completion.  Any combination of these flags may be specified;
the result is a sorted list of all the possibilities.  The options are
as follows.

* Menu:

* Simple Flags::
* Flags with Arguments::
* Control Flags::


File: zsh.info,  Node: Simple Flags,  Next: Flags with Arguments,  Up: Option Flags

21.4.1 Simple Flags
-------------------

These produce completion lists made up by the shell itself:


-f
     Filenames and file system paths.

-/
     Just file system paths.

-c
     Command names, including aliases, shell functions, builtins and
     reserved words.

-F
     Function names.

-B
     Names of builtin commands.

-m
     Names of external commands.

-w
     Reserved words.

-a
     Alias names.

-R
     Names of regular (non-global) aliases.

-G
     Names of global aliases.

-d
     This can be combined with -F, -B, -w, -a, -R and -G to get names
     of disabled functions, builtins, reserved words or aliases.

-e
     This option (to show enabled commands) is in effect by default, but
     may be combined with -d; -de in combination with -F, -B, -w, -a,
     -R and -G will complete names of functions, builtins, reserved
     words or aliases whether or not they are disabled.

-o
     Names of shell options (see *note Options::).

-v
     Names of any variable defined in the shell.

-N
     Names of scalar (non-array) parameters.

-A
     Array names.

-I
     Names of integer variables.

-O
     Names of read-only variables.

-p
     Names of parameters used by the shell (including special
     parameters).

-Z
     Names of shell special parameters.

-E
     Names of environment variables.

-n
     Named directories.

-b
     Key binding names.

-j
     Job names:  the first word of the job leader's command line.  This
     is useful with the kill builtin.

-r
     Names of running jobs.

-z
     Names of suspended jobs.

-u
     User names.



File: zsh.info,  Node: Flags with Arguments,  Next: Control Flags,  Prev: Simple Flags,  Up: Option Flags

21.4.2 Flags with Arguments
---------------------------

These have user supplied arguments to determine how the list of
completions is to be made up:


-k ARRAY
     Names taken from the elements of $ARRAY (note that the `$' does
     not appear on the command line).  Alternatively, the argument
     ARRAY itself may be a set of space- or comma-separated values in
     parentheses, in which any delimiter may be escaped with a
     backslash; in this case the argument should be quoted.  For
     example,


          compctl -k "(cputime filesize datasize stacksize
          	       coredumpsize resident descriptors)" limit

-g GLOBSTRING
     The GLOBSTRING is expanded using filename globbing; it should be
     quoted to protect it from immediate expansion. The resulting
     filenames are taken as the possible completions.  Use `*(/)'
     instead of `*/' for directories.  The fignore special parameter is
     not applied to the resulting files.  More than one pattern may be
     given separated by blanks. (Note that brace expansion is _not_
     part of globbing.  Use the syntax `(either|or)' to match
     alternatives.)

-s SUBSTSTRING
     The SUBSTSTRING is split into words and these words are than
     expanded using all shell expansion mechanisms (see *note
     Expansion::).  The resulting words are taken as possible
     completions.  The fignore special parameter is not applied to the
     resulting files.  Note that -g is faster for filenames.

-K FUNCTION
     Call the given function to get the completions.  Unless the name
     starts with an underscore, the function is passed two arguments:
     the prefix and the suffix of the word on which completion is to be
     attempted, in other words those characters before the cursor
     position, and those from the cursor position onwards.  The whole
     command line can be accessed with the -c and -l flags of the read
     builtin. The function should set the variable reply to an array
     containing the completions (one completion per element); note that
     reply should not be made local to the function.  From such a
     function the command line can be accessed with the -c and -l flags
     to the read builtin.  For example,


          function whoson { reply=(`users`); }
          compctl -K whoson talk

     completes only logged-on users after `talk'.  Note that `whoson'
     must return an array, so `reply=`users`' would be incorrect.

-H NUM PATTERN
     The possible completions are taken from the last NUM history
     lines.  Only words matching PATTERN are taken.  If NUM is zero or
     negative the whole history is searched and if PATTERN is the empty
     string all words are taken (as with `*').  A typical use is


          compctl -D -f + -H 0 ''

     which forces completion to look back in the history list for a
     word if no filename matches.



File: zsh.info,  Node: Control Flags,  Prev: Flags with Arguments,  Up: Option Flags

21.4.3 Control Flags
--------------------

These do not directly specify types of name to be completed, but
manipulate the options that do:


-Q
     This instructs the shell not to quote any metacharacters in the
     possible completions.  Normally the results of a completion are
     inserted into the command line with any metacharacters quoted so
     that they are interpreted as normal characters.  This is
     appropriate for filenames and ordinary strings.  However, for
     special effects, such as inserting a backquoted expression from a
     completion array (-k) so that the expression will not be evaluated
     until the complete line is executed, this option must be used.

-P PREFIX
     The PREFIX is inserted just before the completed string; any
     initial part already typed will be completed and the whole PREFIX
     ignored for completion purposes.  For example,


          compctl -j -P "%" kill

     inserts a `%' after the kill command and then completes job names.

-S SUFFIX
     When a completion is found the SUFFIX is inserted after the
     completed string.  In the case of menu completion the suffix is
     inserted immediately, but it is still possible to cycle through the
     list of completions by repeatedly hitting the same key.

-W FILE-PREFIX
     With directory FILE-PREFIX:  for command, file, directory and
     globbing completion (options -c, -f, -/, -g), the file prefix is
     implicitly added in front of the completion.  For example,


          compctl -/ -W ~/Mail maildirs

     completes any subdirectories to any depth beneath the directory
     ~/Mail, although that prefix does not appear on the command line.
     The FILE-PREFIX may also be of the form accepted by the -k flag,
     i.e. the name of an array or a literal list in parenthesis. In
     this case all the directories in the list will be searched for
     possible completions.

-q
     If used with a suffix as specified by the -S option, this causes
     the suffix to be removed if the next character typed is a blank or
     does not insert anything or if the suffix consists of only one
     character and the next character typed is the same character; this
     the same rule used for the AUTO_REMOVE_SLASH option.  The option
     is most useful for list separators (comma, colon, etc.).

-l CMD
     This option restricts the range of command line words that are
     considered to be arguments.  If combined with one of the extended
     completion patterns `p[...]', `r[...]', or `R[...]'  (see *note
     Extended Completion:: below) the range is restricted to the range
     of arguments specified in the brackets.  Completion is then
     performed as if these had been given as arguments to the CMD
     supplied with the option. If the CMD string is empty the first
     word in the range is instead taken as the command name, and
     command name completion performed on the first word in the range.
     For example,


          compctl -x 'r[-exec,;]' -l '' -- find

     completes arguments between `-exec' and the following `;' (or the
     end of the command line if there is no such string) as if they were
     a separate command line.

-h CMD
     Normally zsh completes quoted strings as a whole. With this option,
     completion can be done separately on different parts of such
     strings. It works like the -l option but makes the completion code
     work on the parts of the current word that are separated by
     spaces. These parts are completed as if they were arguments to the
     given CMD. If CMD is the empty string, the first part is completed
     as a command name, as with -l.

-U
     Use the whole list of possible completions, whether or not they
     actually match the word on the command line.  The word typed so far
     will be deleted.  This is most useful with a function (given by the
     -K option) which can examine the word components passed to it (or
     via the read builtin's -c and -l flags) and use its own criteria
     to decide what matches.  If there is no completion, the original
     word is retained.  Since the produced possible completions seldom
     have interesting common prefixes and suffixes, menu completion is
     started immediately if AUTO_MENU is set and this flag is used.

-y FUNC-OR-VAR
     The list provided by FUNC-OR-VAR is displayed instead of the list
     of completions whenever a listing is required; the actual
     completions to be inserted are not affected.  It can be provided
     in two ways. Firstly, if FUNC-OR-VAR begins with a $ it defines a
     variable, or if it begins with a left parenthesis a literal array,
     which contains the list.  A variable may have been set by a call
     to a function using the -K option.  Otherwise it contains the name
     of a function which will be executed to create the list.  The
     function will be passed as an argument list all matching
     completions, including prefixes and suffixes expanded in full, and
     should set the array reply to the result.  In both cases, the
     display list will only be retrieved after a complete list of
     matches has been created.

     Note that the returned list does not have to correspond, even in
     length, to the original set of matches, and may be passed as a
     scalar instead of an array.  No special formatting of characters is
     performed on the output in this case; in particular, newlines are
     printed literally and if they appear output in columns is
     suppressed.

-X EXPLANATION
     Print EXPLANATION when trying completion on the current set of
     options. A `%n' in this string is replaced by the number of
     matches that were added for this explanation string.  The
     explanation only appears if completion was tried and there was no
     unique match, or when listing completions. Explanation strings
     will be listed together with the matches of the group specified
     together with the -X option (using the -J or -V option). If the
     same explanation string is given to multiple -X options, the
     string appears only once (for each group) and the number of
     matches shown for the `%n' is the total number of all matches for
     each of these uses. In any case, the explanation string will only
     be shown if there was at least one match added for the explanation
     string.

     The sequences %B, %b, %S, %s, %U, and %u specify output attributes
     (bold, standout, and underline), %F, %f, %K, %k specify foreground
     and background colours, and %{...%} can be used to include literal
     escape sequences as in prompts.

-Y EXPLANATION
     Identical to -X, except that the EXPLANATION first undergoes
     expansion following the usual rules for strings in double quotes.
     The expansion will be carried out after any functions are called
     for the -K or -y options, allowing them to set variables.

-t CONTINUE
     The CONTINUE-string contains a character that specifies which set
     of completion flags should be used next.  It is useful:

     (i) With -T, or when trying a list of pattern completions, when
     compctl would usually continue with ordinary processing after
     finding matches; this can be suppressed with `-tn'.

     (ii) With a list of alternatives separated by +, when compctl
     would normally stop when one of the alternatives generates
     matches.  It can be forced to consider the next set of completions
     by adding `-t+' to the flags of the alternative before the `+'.

     (iii) In an extended completion list (see below), when compctl
     would normally continue until a set of conditions succeeded, then
     use only the immediately following flags.  With `-t-', compctl will
     continue trying extended completions after the next `-'; with
     `-tx' it will attempt completion with the default flags, in other
     words those before the `-x'.

-J NAME
     This gives the name of the group the matches should be placed in.
     Groups are listed and sorted separately; likewise, menu completion
     will offer the matches in the groups in the order in which the
     groups were defined. If no group name is explicitly given, the
     matches are stored in a group named DEFAULT. The first time a
     group name is encountered, a group with that name is created.
     After that all matches with the same group name are stored in that
     group.

     This can be useful with non-exclusive alternative completions.  For
     example, in


          compctl -f -J files -t+ + -v -J variables foo

     both files and variables are possible completions, as the -t+
     forces both sets of alternatives before and after the + to be
     considered at once.  Because of the -J options, however, all files
     are listed before all variables.

-V NAME
     Like -J, but matches within the group will not be sorted in
     listings nor in menu completion. These unsorted groups are in a
     different name space from the sorted ones, so groups defined as -J
     files and -V files are distinct.

-1
     If given together with the -V option, makes only consecutive
     duplicates in the group be removed. Note that groups with and
     without this flag are in different name spaces.

-2
     If given together with the -J or -V option, makes all duplicates
     be kept. Again, groups with and without this flag are in different
     name spaces.

-M MATCH-SPEC
     This defines additional matching control specifications that
     should be used only when testing words for the list of flags this
     flag appears in. The format of the MATCH-SPEC string is described
     in *note Completion Matching Control::.



File: zsh.info,  Node: Alternative Completion,  Next: Extended Completion,  Prev: Option Flags,  Up: Completion Using compctl

21.5 Alternative Completion
===========================


compctl [ -CDT ] OPTIONS + OPTIONS [ + ... ] [ + ] COMMAND ...


The form with `+' specifies alternative options. Completion is tried
with the options before the first `+'. If this produces no matches
completion is tried with the flags after the `+' and so on. If there
are no flags after the last `+' and a match has not been found up to
that point, default completion is tried.  If the list of flags contains
a -t with a + character, the next list of flags is used even if the
current list produced matches.



File: zsh.info,  Node: Extended Completion,  Next: Example,  Prev: Alternative Completion,  Up: Completion Using compctl

Additional options are available that restrict completion to some part
of the command line; this is referred to as `extended completion'.



21.6 Extended Completion
========================


compctl [ -CDT ] OPTIONS -x PATTERN OPTIONS - ... --

[ COMMAND ... ]

compctl [ -CDT ] OPTIONS [ -x PATTERN OPTIONS - ... -- ]

[ + OPTIONS [ -x ... -- ] ... [+] ] [ COMMAND ... ]


The form with `-x' specifies extended completion for the commands
given; as shown, it may be combined with alternative completion using
`+'.  Each PATTERN is examined in turn; when a match is found, the
corresponding OPTIONS, as described in *note Option Flags:: above, are
used to generate possible completions.  If no PATTERN matches, the
OPTIONS given before the -x are used.

Note that each pattern should be supplied as a single argument and
should be quoted to prevent expansion of metacharacters by the shell.

A PATTERN is built of sub-patterns separated by commas; it matches if
at least one of these sub-patterns matches (they are `or'ed). These
sub-patterns are in turn composed of other sub-patterns separated by
white spaces which match if all of the sub-patterns match (they are
`and'ed).  An element of the sub-patterns is of the form `C[...][...]',
where the pairs of brackets may be repeated as often as necessary, and
matches if any of the sets of brackets match (an `or').  The example
below makes this clearer.

The elements may be any of the following:


s[STRING]...
     Matches if the current word on the command line starts with one of
     the strings given in brackets.  The STRING is not removed and is
     not part of the completion.

S[STRING]...
     Like s[STRING] except that the STRING is part of the completion.

p[FROM,TO]...
     Matches if the number of the current word is between one of the
     FROM and TO pairs inclusive. The comma and TO are optional; TO
     defaults to the same value as FROM.  The numbers may be negative:
     -N refers to the N'th last word on the line.

c[OFFSET,STRING]...
     Matches if the STRING matches the word offset by OFFSET from the
     current word position.  Usually OFFSET will be negative.

C[OFFSET,PATTERN]...
     Like c but using pattern matching instead.

w[INDEX,STRING]...
     Matches if the word in position INDEX is equal to the
     corresponding STRING.  Note that the word count is made after any
     alias expansion.

W[INDEX,PATTERN]...
     Like w but using pattern matching instead.

n[INDEX,STRING]...
     Matches if the current word contains STRING.  Anything up to and
     including the INDEXth occurrence of this string will not be
     considered part of the completion, but the rest will.  INDEX may
     be negative to count from the end: in most cases, INDEX will be 1
     or -1.  For example,


          compctl -s '`users`' -x 'n[1,@]' -k hosts -- talk

     will usually complete usernames, but if you insert an @ after the
     name, names from the array HOSTS (assumed to contain hostnames,
     though you must make the array yourself) will be completed.  Other
     commands such as rcp can be handled similarly.

N[INDEX,STRING]...
     Like n except that the string will be taken as a character class.
     Anything up to and including the INDEXth occurrence of any of the
     characters in STRING will not be considered part of the completion.

m[MIN,MAX]...
     Matches if the total number of words lies between MIN and MAX
     inclusive.

r[STR1,STR2]...
     Matches if the cursor is after a word with prefix STR1.  If there
     is also a word with prefix STR2 on the command line after the one
     matched by STR1 it matches only if the cursor is before this word.
     If the comma and STR2 are omitted, it matches if the cursor is
     after a word with prefix STR1.

R[STR1,STR2]...
     Like r but using pattern matching instead.

q[STR]...
     Matches the word currently being completed is in single quotes and
     the STR begins with the letter `s', or if completion is done in
     double quotes and STR starts with the letter `d', or if completion
     is done in backticks and STR starts with a `b'.



File: zsh.info,  Node: Example,  Prev: Extended Completion,  Up: Completion Using compctl

21.7 Example
============


     compctl -u -x 's[+] c[-1,-f],s[-f+]' \
       -g '~/Mail/*(:t)' - 's[-f],c[-1,-f]' -f -- mail

This is to be interpreted as follows:

If the current command is mail, then



     if ((the current word begins with + and the previous word is -f)
     or (the current word begins with -f+)), then complete the
     non-directory part (the `:t' glob modifier) of files in the
     directory ~/Mail; else

     if the current word begins with -f or the previous word was -f,
     then complete any file; else

     complete user names.


File: zsh.info,  Node: Zsh Modules,  Next: Calendar Function System,  Prev: Completion Using compctl,  Up: Top

22 Zsh Modules
**************



22.1 Description
================

Some optional parts of zsh are in modules, separate from the core of
the shell.  Each of these modules may be linked in to the shell at
build time, or can be dynamically linked while the shell is running if
the installation supports this feature.  The modules that are bundled
with the zsh distribution are:


zsh/attr
     Builtins for manipulating extended attributes (xattr).

zsh/cap
     Builtins for manipulating POSIX.1e (POSIX.6) capability
     (privilege) sets.

zsh/clone
     A builtin that can clone a running shell onto another terminal.

zsh/compctl
     The compctl builtin for controlling completion.

zsh/complete
     The basic completion code.

zsh/complist
     Completion listing extensions.

zsh/computil
     A module with utility builtins needed for the shell function based
     completion system.

zsh/curses
     curses windowing commands

zsh/datetime
     Some date/time commands and parameters.

zsh/deltochar
     A ZLE function duplicating EMACS' zap-to-char.

zsh/example
     An example of how to write a module.

zsh/files
     Some basic file manipulation commands as builtins.

zsh/mapfile
     Access to external files via a special associative array.

zsh/mathfunc
     Standard scientific functions for use in mathematical evaluations.

zsh/newuser
     Arrange for files for new users to be installed.

zsh/parameter
     Access to internal hash tables via special associative arrays.

zsh/pcre
     Interface to the PCRE library.

zsh/regex
     Interface to the POSIX regex library.

zsh/sched
     A builtin that provides a timed execution facility within the
     shell.

zsh/net/socket
     Manipulation of Unix domain sockets

zsh/stat
     A builtin command interface to the stat system call.

zsh/system
     A builtin interface to various low-level system features.

zsh/net/tcp
     Manipulation of TCP sockets

zsh/termcap
     Interface to the termcap database.

zsh/terminfo
     Interface to the terminfo database.

zsh/zftp
     A builtin FTP client.

zsh/zle
     The Zsh Line Editor, including the bindkey and vared builtins.

zsh/zleparameter
     Access to internals of the Zsh Line Editor via parameters.

zsh/zprof
     A module allowing profiling for shell functions.

zsh/zpty
     A builtin for starting a command in a pseudo-terminal.

zsh/zselect
     Block and return when file descriptors are ready.

zsh/zutil
     Some utility builtins, e.g. the one for supporting configuration
     via styles.


* Menu:

* The zsh/attr Module::
* The zsh/cap Module::
* The zsh/clone Module::
* The zsh/compctl Module::
* The zsh/complete Module::
* The zsh/complist Module::
* The zsh/computil Module::
* The zsh/curses Module::
* The zsh/datetime Module::
* The zsh/deltochar Module::
* The zsh/example Module::
* The zsh/files Module::
* The zsh/mapfile Module::
* The zsh/mathfunc Module::
* The zsh/newuser Module::
* The zsh/parameter Module::
* The zsh/pcre Module::
* The zsh/regex Module::
* The zsh/sched Module::
* The zsh/net/socket Module::
* The zsh/stat Module::
* The zsh/system Module::
* The zsh/net/tcp Module::
* The zsh/termcap Module::
* The zsh/terminfo Module::
* The zsh/zftp Module::
* The zsh/zle Module::
* The zsh/zleparameter Module::
* The zsh/zprof Module::
* The zsh/zpty Module::
* The zsh/zselect Module::
* The zsh/zutil Module::

File: zsh.info,  Node: The zsh/attr Module,  Next: The zsh/cap Module,  Up: Zsh Modules

22.2 The zsh/attr Module
========================



   The zsh/attr module is used for manipulating extended attributes.
The -h option causes all commands to operate on symbolic links instead
of their targets.  The builtins in this module are:


zgetattr [ -h ] FILENAME ATTRIBUTE [ PARAMETER ]
     Get the extended attribute ATTRIBUTE from the specified FILENAME.
     If the optional argument PARAMETER is given, the attribute is set
     on that parameter instead of being printed to stdout.

zsetattr [ -h ] FILENAME ATTRIBUTE VALUE
     Set the extended attribute ATTRIBUTE on the specified FILENAME to
     VALUE.

zdelattr [ -h ] FILENAME ATTRIBUTE
     Remove the extended attribute ATTRIBUTE from the specified
     FILENAME.

zlistattr [ -h ] FILENAME [ PARAMETER ]
     List the extended attributes currently set on the specified
     FILENAME. If the optional argument PARAMETER is given, the list of
     attributes is set on that parameter instead of being printed to
     stdout.


zgetattr and zlistattr allocate memory dynamically.  If the attribute
or list of attributes grows between the allocation and the call to get
them, they return 2.  On all other errors, 1 is returned.  This allows
the calling function to check for this case and retry.

File: zsh.info,  Node: The zsh/cap Module,  Next: The zsh/clone Module,  Prev: The zsh/attr Module,  Up: Zsh Modules

22.3 The zsh/cap Module
=======================



   The zsh/cap module is used for manipulating POSIX.1e (POSIX.6)
capability sets.  If the operating system does not support this
interface, the builtins defined by this module will do nothing.  The
builtins in this module are:


cap [ CAPABILITIES ]
     Change the shell's process capability sets to the specified
     CAPABILITIES, otherwise display the shell's current capabilities.

getcap FILENAME ...
     This is a built-in implementation of the POSIX standard utility.
     It displays the capability sets on each specified FILENAME.

setcap CAPABILITIES FILENAME ...
     This is a built-in implementation of the POSIX standard utility.
     It sets the capability sets on each specified FILENAME to the
     specified CAPABILITIES.


File: zsh.info,  Node: The zsh/clone Module,  Next: The zsh/compctl Module,  Prev: The zsh/cap Module,  Up: Zsh Modules

22.4 The zsh/clone Module
=========================



   The zsh/clone module makes available one builtin command:


clone TTY
     Creates a forked instance of the current shell, attached to the
     specified TTY.  In the new shell, the PID, PPID and TTY special
     parameters are changed appropriately.  $! is set to zero in the new
     shell, and to the new shell's PID in the original shell.

     The return status of the builtin is zero in both shells if
     successful, and non-zero on error.

     The target of clone should be an unused terminal, such as an
     unused virtual console or a virtual terminal created by

     xterm -e sh -c 'trap : INT QUIT TSTP; tty; while :; do sleep
     100000000; done'

     Some words of explanation are warranted about this long xterm
     command line: when doing clone on a pseudo-terminal, some other
     session ("session" meant as a unix session group, or SID) is
     already owning the terminal. Hence the cloned zsh cannot acquire
     the pseudo-terminal as a controlling tty. That means two things:

     the job control signals will go to the sh-started-by-xterm process
          group (that's why we disable INT QUIT and TSTP with trap;
     otherwise       the while loop could get suspended or killed)

     the cloned shell will have job control disabled, and the job
     control keys (control-C, control-\ and control-Z) will not work.

     This does not apply when cloning to an `unused' vc.

     Cloning to a used (and unprepared) terminal will result in two
     processes reading simultaneously from the same terminal, with
     input bytes going randomly to either process.

     clone is mostly useful as a shell built-in replacement for openvt.


File: zsh.info,  Node: The zsh/compctl Module,  Next: The zsh/complete Module,  Prev: The zsh/clone Module,  Up: Zsh Modules

22.5 The zsh/compctl Module
===========================



   The zsh/compctl module makes available two builtin commands. compctl,
is the old, deprecated way to control completions for ZLE.  See *note
Completion Using compctl::.  The other builtin command, compcall can be
used in user-defined completion widgets, see *note Completion Widgets::.

File: zsh.info,  Node: The zsh/complete Module,  Next: The zsh/complist Module,  Prev: The zsh/compctl Module,  Up: Zsh Modules

22.6 The zsh/complete Module
============================



   The zsh/complete module makes available several builtin commands
which can be used in user-defined completion widgets, see *note
Completion Widgets::.

File: zsh.info,  Node: The zsh/complist Module,  Next: The zsh/computil Module,  Prev: The zsh/complete Module,  Up: Zsh Modules

22.7 The zsh/complist Module
============================



   The zsh/complist module offers three extensions to completion
listings: the ability to highlight matches in such a list, the ability
to scroll through long lists and a different style of menu completion.



22.7.1 Colored completion listings
----------------------------------

Whenever one of the parameters ZLS_COLORS or ZLS_COLOURS is set and the
zsh/complist module is loaded or linked into the shell, completion
lists will be colored.  Note, however, that complist will not
automatically be loaded if it is not linked in:  on systems with
dynamic loading, `zmodload zsh/complist' is required.

The parameters ZLS_COLORS and ZLS_COLOURS describe how matches are
highlighted.  To turn on highlighting an empty value suffices, in which
case all the default values given below will be used.  The format of
the value of these parameters is the same as used by the GNU version of
the ls command: a colon-separated list of specifications of the form
`NAME=VALUE'.  The NAME may be one of the following strings, most of
which specify file types for which the VALUE will be used.  The strings
and their default values are:


no 0
     for normal text (i.e. when displaying something other than a
     matched file)

fi 0
     for regular files

di 32
     for directories

ln 36
     for symbolic links.  If this has the special value target,
     symbolic links are dereferenced and the target file used to
     determine the display format.

pi 31
     for named pipes (FIFOs)

so 33
     for sockets

bd 44;37
     for block devices

cd 44;37
     for character devices

or NONE
     for a symlink to nonexistent file (default is the value defined
     for ln)

mi NONE
     for a non-existent file (default is the value defined for fi);
     this code is currently not used

su 37;41
     for files with setuid bit set

sg 30;43
     for files with setgid bit set

tw 30;42
     for world writable directories with sticky bit set

ow 34;43
     for world writable directories without sticky bit set

sa NONE
     for files with an associated suffix alias; this is only tested
     after specific suffixes, as described below

st 37;44
     for directories with sticky bit set but not world writable

ex 35
     for executable files

lc \e[
     for the left code (see below)

rc m
     for the right code

tc 0
     for the character indicating the file type  printed after
     filenames if the LIST_TYPES option is set

sp 0
     for the spaces printed after matches to align the next column

ec NONE
     for the end code


Apart from these strings, the NAME may also be an asterisk (`*')
followed by any string. The VALUE given for such a string will be used
for all files whose name ends with the string.  The NAME may also be an
equals sign (`=') followed by a pattern; the EXTENDED_GLOB option will
be turned on for evaluation of the pattern.  The VALUE given for this
pattern will be used for all matches (not just filenames) whose display
string are matched by the pattern.  Definitions for the form with the
leading equal sign take precedence over the values defined for file
types, which in turn take precedence over the form with the leading
asterisk (file extensions).

The leading-equals form also allows different parts of the displayed
strings to be colored differently.  For this, the pattern has to use the
`(#b)' globbing flag and pairs of parentheses surrounding the parts of
the strings that are to be colored differently.  In this case the VALUE
may consist of more than one color code separated by equal signs.  The
first code will be used for all parts for which no explicit code is
specified and the following codes will be used for the parts matched by
the sub-patterns in parentheses.  For example, the specification
`=(#b)(?)*(?)=0=3=7' will be used for all matches which are at least
two characters long and will use the code `3' for the first character,
`7' for the last character and `0' for the rest.

All three forms of NAME may be preceded by a pattern in parentheses.
If this is given, the VALUE will be used only for matches in groups
whose names are matched by the pattern given in the parentheses.  For
example, `(g*)m*=43' highlights all matches beginning with `m' in
groups whose names  begin with `g' using the color code `43'.  In case
of the `lc', `rc', and `ec' codes, the group pattern is ignored.

Note also that all patterns are tried in the order in which they appear
in the parameter value until the first one matches which is then used.

When printing a match, the code prints the value of lc, the value for
the file-type or the last matching specification with a `*', the value
of rc, the string to display for the match itself, and then the value
of ec if that is defined or the values of lc, no, and rc if ec is not
defined.

The default values are ISO 6429 (ANSI) compliant and can be used on
vt100 compatible terminals such as xterms.  On monochrome terminals the
default values will have no visible effect.  The colors function from
the contribution can be used to get associative arrays containing the
codes for ANSI terminals (see *note Other Functions::).  For example,
after loading colors, one could use `$colors[red]' to get the code for
foreground color red and `$colors[bg-green]' for the code for
background color green.

If the completion system invoked by compinit is used, these parameters
should not be set directly because the system controls them itself.
Instead, the list-colors style should be used (see *note Completion
System Configuration::).



22.7.2 Scrolling in completion listings
---------------------------------------

To enable scrolling through a completion list, the LISTPROMPT parameter
must be set.  Its value will be used as the prompt; if it is the empty
string, a default prompt will be used.  The value may contain escapes
of the form `%x'.  It supports the escapes `%B', `%b', `%S', `%s',
`%U', `%u', `%F', `%f', `%K', `%k' and `%{...%}' used also in shell
prompts as well as three pairs of additional sequences: a `%l' or `%L'
is replaced by the number of the last line shown and the total number
of lines in the form `NUMBER/TOTAL'; a `%m' or `%M' is replaced with
the number of the last match shown and the total number of matches; and
`%p' or `%P' is replaced with `Top', `Bottom' or the position of the
first line shown in percent of the total number of lines, respectively.
In each of these cases the form with the uppercase letter will be
replaced with a string of fixed width, padded to the right with spaces,
while the lowercase form will not be padded.

If the parameter LISTPROMPT is set, the completion code will not ask if
the list should be shown.  Instead it immediately starts displaying the
list, stopping after the first screenful, showing the prompt at the
bottom, waiting for a keypress after temporarily switching to the
listscroll keymap.  Some of the zle functions have a special meaning
while scrolling lists:


send-break
     stops listing discarding the key pressed

accept-line, down-history, down-line-or-history
down-line-or-search, vi-down-line-or-history
     scrolls forward one line

complete-word, menu-complete, expand-or-complete
expand-or-complete-prefix, menu-complete-or-expand
     scrolls forward one screenful

accept-search
     stop listing but take no other action


Every other character stops listing and immediately processes the key
as usual.  Any key that is not bound in the listscroll keymap or that
is bound to undefined-key is looked up in the keymap currently selected.

As for the ZLS_COLORS and ZLS_COLOURS parameters, LISTPROMPT should not
be set directly when using the shell function based completion system.
Instead, the list-prompt style should be used.



22.7.3 Menu selection
---------------------

The zsh/complist module also offers an alternative style of selecting
matches from a list, called menu selection, which can be used if the
shell is set up to return to the last prompt after showing a completion
list (see the ALWAYS_LAST_PROMPT option in *note Options::).

Menu selection can be invoked directly by the widget menu-select
defined by this module.  This is a standard ZLE widget that can be
bound to a key in the usual way as described in *note Zsh Line Editor::.

Alternatively, the parameter MENUSELECT can be set to an integer, which
gives the minimum number of matches that must be present before menu
selection is automatically turned on.  This second method requires that
menu completion be started, either directly from a widget such as
menu-complete, or due to one of the options MENU_COMPLETE or AUTO_MENU
being set.  If MENUSELECT is set, but is 0, 1 or empty, menu selection
will always be started during an ambiguous menu completion.

When using the completion system based on shell functions, the
MENUSELECT parameter should not be used (like the ZLS_COLORS and
ZLS_COLOURS parameters described above).  Instead, the menu style
should be used with the select=... keyword.

After menu selection is started, the matches will be listed. If there
are more matches than fit on the screen, only the first screenful is
shown.  The matches to insert into the command line can be selected
from this list.  In the list one match is highlighted using the value
for ma from the ZLS_COLORS or ZLS_COLOURS parameter.  The default value
for this is `7' which forces the selected match to be highlighted using
standout mode on a vt100-compatible terminal.  If neither ZLS_COLORS
nor ZLS_COLOURS is set, the same terminal control sequence as for the
`%S' escape in prompts is used.

If there are more matches than fit on the screen and the parameter
MENUPROMPT is set, its value will be shown below the matches.  It
supports the same escape sequences as LISTPROMPT, but the number of the
match or line shown will be that of the one where the mark is placed.
If its value is the empty string, a default prompt will be used.

The MENUSCROLL parameter can be used to specify how the list is
scrolled.  If the parameter is unset, this is done line by line, if it
is set to `0' (zero), the list will scroll half the number of lines of
the screen.  If the value is positive, it gives the number of lines to
scroll and if it is negative, the list will be scrolled the number of
lines of the screen minus the (absolute) value.

As for the ZLS_COLORS, ZLS_COLOURS and LISTPROMPT parameters, neither
MENUPROMPT nor MENUSCROLL should be set directly when using the shell
function based completion system.  Instead, the select-prompt and
select-scroll styles should be used.

The completion code sometimes decides not to show all of the matches in
the list.  These hidden matches are either matches for which the
completion function which added them explicitly requested that they not
appear in the list (using the -n option of the compadd builtin command)
or they are matches which duplicate a string already in the list
(because they differ only in things like prefixes or suffixes that are
not displayed).  In the list used for menu selection, however, even
these matches are shown so that it is possible to select them.  To
highlight such matches the hi and du capabilities in the ZLS_COLORS and
ZLS_COLOURS parameters are supported for hidden matches of the first
and second kind, respectively.

Selecting matches is done by moving the mark around using the zle
movement functions.  When not all matches can be shown on the screen at
the same time, the list will scroll up and down when crossing the top or
bottom line.  The following zle functions have special meaning during
menu selection.  Note that the following always perform the same task
within the menu selection map and cannot be replaced by user defined
widgets, nor can the set of functions be extended:


accept-line, accept-search
     accept the current match and leave menu selection (but do not
     cause the command line to be accepted)

send-break
     leaves menu selection and restores the previous contents of the
     command line

redisplay, clear-screen
     execute their normal function without leaving menu selection

accept-and-hold, accept-and-menu-complete
     accept the currently inserted match and continue selection
     allowing to select the next match to insert into the line

accept-and-infer-next-history
     accepts the current match and then tries completion with menu
     selection again;  in the case of files this allows one to select a
     directory and immediately attempt to complete files in it;  if
     there are no matches, a message is shown and one can use undo to
     go back to completion on the previous level, every other key
     leaves menu selection (including the other zle functions which are
     otherwise special during menu selection)

undo
     removes matches inserted during the menu selection by one of the
     three functions before

down-history, down-line-or-history
vi-down-line-or-history,  down-line-or-search
     moves the mark one line down

up-history, up-line-or-history
vi-up-line-or-history, up-line-or-search
     moves the mark one line up

forward-char, vi-forward-char
     moves the mark one column right

backward-char, vi-backward-char
     moves the mark one column left

forward-word, vi-forward-word
vi-forward-word-end, emacs-forward-word
     moves the mark one screenful down

backward-word, vi-backward-word, emacs-backward-word
     moves the mark one screenful up

vi-forward-blank-word, vi-forward-blank-word-end
     moves the mark to the first line of the next group of matches

vi-backward-blank-word
     moves the mark to the last line of the previous group of matches

beginning-of-history
     moves the mark to the first line

end-of-history
     moves the mark to the last line

beginning-of-buffer-or-history, beginning-of-line
beginning-of-line-hist, vi-beginning-of-line
     moves the mark to the leftmost column

end-of-buffer-or-history, end-of-line
end-of-line-hist, vi-end-of-line
     moves the mark to the rightmost column

complete-word, menu-complete, expand-or-complete
expand-or-complete-prefix, menu-expand-or-complete
     moves the mark to the next match

reverse-menu-complete
     moves the mark to the previous match

vi-insert
     this toggles between normal and interactive mode; in interactive
     mode the keys bound to self-insert and self-insert-unmeta insert
     into the command line as in normal editing mode but without leaving
     menu selection; after each character completion is tried again and
     the list changes to contain only the new matches; the completion
     widgets make the longest unambiguous string be inserted in the
     command line and undo and backward-delete-char go back to the
     previous set of matches

history-incremental-search-forward,
     history-incremental-search-backward this starts incremental
     searches in the list of completions displayed; in this mode,
     accept-line only leaves incremental search, going back to the
     normal menu selection mode


All movement functions wrap around at the edges; any other zle function
not listed leaves menu selection and executes that function.  It is
possible to make widgets in the above list do the same by using the
form of the widget with a `.' in front.  For example, the widget
`.accept-line' has the effect of leaving menu selection and accepting
the entire command line.

During this selection the widget uses the keymap menuselect.  Any key
that is not defined in this keymap or that is bound to undefined-key is
looked up in the keymap currently selected.  This is used to ensure
that the most important keys used during selection (namely the cursor
keys, return, and TAB) have sensible defaults.  However, keys in the
menuselect keymap can be modified directly using the bindkey builtin
command (see *note The zsh/zle Module::). For example, to make the
return key leave menu selection without accepting the match currently
selected one could call



     bindkey -M menuselect '^M' send-break

after loading the zsh/complist module.

File: zsh.info,  Node: The zsh/computil Module,  Next: The zsh/curses Module,  Prev: The zsh/complist Module,  Up: Zsh Modules

22.8 The zsh/computil Module
============================



   The zsh/computil module adds several builtin commands that are used
by some of the completion functions in the completion system based on
shell functions (see *note Completion System:: ).  Except for compquote
these builtin commands are very specialised and thus not very
interesting when writing your own completion functions.  In summary,
these builtin commands are:


comparguments
     This is used by the _arguments function to do the argument and
     command line parsing.  Like compdescribe it has an option -i to do
     the parsing and initialize some internal state and various options
     to access the state information to decide what should be completed.

compdescribe
     This is used by the _describe function to build the displays for
     the matches and to get the strings to add as matches with their
     options.  On the first call one of the options -i or -I should be
     supplied as the first argument.  In the first case, display
     strings without the descriptions will be generated, in the second
     case, the string used to separate the matches from their
     descriptions must be given as the second argument and the
     descriptions (if any) will be shown.  All other arguments are like
     the definition arguments to _describe itself.

     Once compdescribe has been called with either the -i or the -I
     option, it can be repeatedly called with the -g option and the
     names of five arrays as its arguments.  This will step through the
     different sets of matches and store the options in the first array,
     the strings with descriptions in the second, the matches for these
     in the third, the strings without descriptions in the fourth, and
     the matches for them in the fifth array.  These are then directly
     given to compadd to register the matches with the completion code.

compfiles
     Used by the _path_files function to optimize complex recursive
     filename generation (globbing).  It does three things.  With the
     -p and -P options it builds the glob patterns to use, including
     the paths already handled and trying to optimize the patterns with
     respect to the prefix and suffix from the line and the match
     specification currently used.  The -i option does the directory
     tests for the ignore-parents style and the -r option tests if a
     component for some of the matches are equal to the string on the
     line and removes all other matches if that is true.

compgroups
     Used by the _tags function to implement the internals of the
     group-order style.  This only takes its arguments as names of
     completion groups and creates the groups for it (all six types:
     sorted and unsorted, both without removing duplicates, with
     removing all duplicates and with removing consecutive duplicates).

compquote [ -p ] NAMES ...
     There may be reasons to write completion functions that have to add
     the matches using the -Q option to compadd and perform quoting
     themselves.  Instead of interpreting the first character of the
     all_quotes key of the compstate special association and using the
     q flag for parameter expansions, one can use this builtin command.
     The arguments are the names of scalar or array parameters and the
     values of these parameters are quoted as needed for the innermost
     quoting level.  If the -p option is given, quoting is done as if
     there is some prefix before the values of the parameters, so that
     a leading equal sign will not be quoted.

     The return status is non-zero in case of an error and zero
     otherwise.

comptags
comptry
     These implement the internals of the tags mechanism.

compvalues
     Like comparguments, but for the _values function.


File: zsh.info,  Node: The zsh/curses Module,  Next: The zsh/datetime Module,  Prev: The zsh/computil Module,  Up: Zsh Modules

22.9 The zsh/curses Module
==========================



   The zsh/curses module makes available one builtin command and
various parameters.



22.9.1 Builtin
--------------


zcurses init
zcurses end
zcurses addwin TARGETWIN NLINES NCOLS BEGIN_Y BEGIN_X [ PARENTWIN ]
zcurses delwin TARGETWIN
zcurses refresh [ TARGETWIN ... ]
zcurses touch TARGETWIN ...
zcurses move TARGETWIN NEW_Y NEW_X
zcurses clear TARGETWIN [ redraw | eol | bot ]
zcurses position TARGETWIN ARRAY
zcurses char TARGETWIN CHARACTER
zcurses string TARGETWIN STRING
zcurses border TARGETWIN BORDER
zcurses attr TARGETWIN [ {+/-}ATTRIBUTE | FG_COL/BG_COL ] [...]
zcurses bg TARGETWIN [ {+/-}ATTRIBUTE | FG_COL/BG_COL | @CHAR ] [...]
zcurses scroll TARGETWIN [ on | off | {+/-}LINES ]
zcurses input TARGETWIN [ PARAM [ KPARAM [ MPARAM ] ] ]
zcurses mouse [ delay NUM | {+/-}motion ]
zcurses timeout TARGETWIN INTVAL
zcurses querychar TARGETWIN [ PARAM ]
     Manipulate curses windows.  All uses of this command should be
     bracketed by `zcurses init' to initialise use of curses, and
     `zcurses end' to end it; omitting `zcurses end' can cause the
     terminal to be in an unwanted state.

     The subcommand addwin creates a window with NLINES lines and NCOLS
     columns.  Its upper left corner will be placed at row BEGIN_Y and
     column BEGIN_X of the screen.  TARGETWIN is a string and refers to
     the name of a window that is not currently assigned.  Note in
     particular the curses convention that vertical values appear
     before horizontal values.

     If addwin is given an existing window as the final argument, the
     new window is created as a subwindow of PARENTWIN.  This differs
     from an ordinary new window in that the memory of the window
     contents is shared with the parent's memory.  Subwindows must be
     deleted before their parent.  Note that the coordinates of
     subwindows are relative to the screen, not the parent, as with
     other windows.

     Use the subcommand delwin to delete a window created with addwin.
     Note that end does _not_ implicitly delete windows, and that
     delwin does not erase the screen image of the window.

     The window corresponding to the full visible screen is called
     stdscr; it always exists after `zcurses init' and cannot be delete
     with delwin.

     The subcommand refresh will refresh window TARGETWIN; this is
     necessary to make any pending changes (such as characters you have
     prepared for output with char) visible on the screen.  refresh
     without an argument causes the screen to be cleared and redrawn.
     If multiple windows are given, the screen is updated once at the
     end.

     The subcommand touch marks the TARGETWINs listed as changed.  This
     is necessary before refreshing windows if a window that was in
     front of another window (which may be stdscr) is deleted.

     The subcommand move moves the cursor position in TARGETWIN to new
     coordinates NEW_Y and NEW_X.  Note that the subcommand string (but
     not the subcommand char) advances the cursor position over the
     characters added.

     The subcommand clear erases the contents of TARGETWIN.  One (and
     no more than one) of three options may be specified.  With the
     option redraw, in addition the next refresh of TARGETWIN will
     cause the screen to be cleared and repainted.  With the option
     eol, TARGETWIN is only cleared to the end of the current cursor
     line.  With the option bot, TARGETWIN is cleared to the end of the
     window, i.e everything to the right and below the cursor is
     cleared.

     The subcommand position writes various positions associated with
     TARGETWIN into the array named ARRAY.  These are, in order:

          The y and x coordinates of the cursor relative to the top left
          of TARGETWIN


          The y and x coordinates of the top left of TARGETWIN on the
          screen


          The size of TARGETWIN in y and x dimensions.

     Outputting characters and strings are achieved by char and string
     respectively.

     To draw a border around window TARGETWIN, use border.  Note that
     the border is not subsequently handled specially:  in other words,
     the border is simply a set of characters output at the edge of the
     window.  Hence it can be overwritten, can scroll off the window,
     etc.

     The subcommand attr will set TARGETWIN's attributes or
     foreground/background color pair for any successive character
     output.  Each ATTRIBUTE given on the line may be prepended by a +
     to set or a - to unset that attribute; + is assumed if absent.  The
     attributes supported are blink, bold, dim, reverse, standout, and
     underline.

     Each FG_COL/BG_COL attribute (to be read as `FG_COL on BG_COL')
     sets the foreground and background color for character output.
     The color default is sometimes available (in particular if the
     library is ncurses), specifying the foreground or background color
     with which the terminal started.  The color pair default/default
     is always available.

     bg overrides the color and other attributes of all characters in
     the window.  Its usual use is to set the background initially, but
     it will overwrite the attributes of any characters at the time
     when it is called.  In addition to the arguments allowed with
     attr, an argument @CHAR specifies a character to be shown in
     otherwise blank areas of the window.  Owing to limitations of
     curses this cannot be a multibyte character (use of ASCII
     characters only is recommended).  As the specified set of
     attributes override the existing background, turning attributes
     off in the arguments is not useful, though this does not cause an
     error.

     The subcommand scroll can be used with on or off to enabled or
     disable scrolling of a window when the cursor would otherwise move
     below the window due to typing or output.  It can also be used
     with a positive or negative integer to scroll the window up or
     down the given number of lines without changing the current cursor
     position (which therefore appears to move in the opposite
     direction relative to the window).  In the second case, if
     scrolling is off it is temporarily turned on to allow the window
     to be scrolled.

     The subcommand input reads a single character from the window
     without echoing it back.  If PARAM is supplied the character is
     assigned to the parameter PARAM, else it is assigned to the
     parameter REPLY.

     If both PARAM and KPARAM are supplied, the key is read in `keypad'
     mode.  In this mode special keys such as function keys and arrow
     keys return the name of the key in the parameter KPARAM.  The key
     names are the macros defined in the curses.h or ncurses.h with the
     prefix `KEY_' removed; see also the description of the parameter
     zcurses_keycodes below.  Other keys cause a value to be set in
     PARAM as before.  On a successful return only one of PARAM or
     KPARAM contains a non-empty string; the other is set to an empty
     string.

     If MPARAM is also supplied, input attempts to handle mouse input.
     This is only available with the ncurses library; mouse handling
     can be detected by checking for the exit status of `zcurses mouse'
     with no arguments.  If a mouse button is clicked (or double- or
     triple-clicked, or pressed or released with a configurable delay
     from being clicked) then kparam is set to the string MOUSE, and
     MPARAM is set to an array consisting of the following elements:
    -
          An identifier to discriminate different input devices; this
          is only rarely useful.

    -
          The x, y and z coordinates of the mouse click relative to the
          full screen, as three elements in that order (i.e. the y
          coordinate is, unusually, after the x coordinate).  The z
          coordinate is only available for a few unusual input devices
          and is otherwise set to zero.

    -
          Any events that occurred as separate items; usually there
          will be just one.  An event consists of PRESSED, RELEASED,
          CLICKED, DOUBLE_CLICKED or TRIPLE_CLICKED followed
          immediately (in the same element) by the number of the button.

    -
          If the shift key was pressed, the string SHIFT.

    -
          If the control key was pressed, the string CTRL.

    -
          If the alt key was pressed, the string ALT.

     Not all mouse events may be passed through to the terminal window;
     most terminal emulators handle some mouse events themselves.  Note
     that the ncurses manual implies that using input both with and
     without mouse handling may cause the mouse cursor to appear and
     disappear.

     The subcommand mouse can be used to configure the use of the mouse.
     There is no window argument; mouse options are global.  `zcurses
     mouse' with no arguments returns status 0 if mouse handling is
     possible, else status 1.  Otherwise, the possible arguments (which
     may be combined on the same command line) are as follows.  delay
     NUM sets the maximum delay in milliseconds between press and
     release events to be considered as a click; the value 0 disables
     click resolution, and the default is one sixth of a second.
     motion proceeded by an optional `+' (the default) or - turns on or
     off reporting of mouse motion in addition to clicks, presses and
     releases, which are always reported.  However, it appears reports
     for mouse motion are not currently implemented.

     The subcommand timeout specifies a timeout value for input from
     TARGETWIN.  If INTVAL is negative, `zcurses input' waits
     indefinitely for a character to be typed; this is the default.  If
     INTVAL is zero, `zcurses input' returns immediately; if there is
     typeahead it is returned, else no input is done and status 1 is
     returned.  If INTVAL is positive, `zcurses input' waits INTVAL
     milliseconds for input and if there is none at the end of that
     period returns status 1.

     The subcommand querychar queries the character at the current
     cursor position.  The return values are stored in the array named
     PARAM if supplied, else in the array reply.  The first value is
     the character (which may be a multibyte character if the system
     supports them); the second is the color pair in the usual
     FG_COL/BG_COL notation, or 0 if color is not supported.  Any
     attributes other than color that apply to the character, as set
     with the subcommand attr, appear as additional elements.



22.9.2 Parameters
-----------------


ZCURSES_COLORS
     Readonly integer.  The maximum number of colors the terminal
     supports.  This value is initialised by the curses library and is
     not available until the first time zcurses init is run.

ZCURSES_COLOR_PAIRS
     Readonly integer.  The maximum number of color pairs FG_COL/BG_COL
     that may be defined in `zcurses attr' commands; note this limit
     applies to all color pairs that have been used whether or not they
     are currently active.  This value is initialised by the curses
     library and is not available until the first time zcurses init is
     run.

zcurses_attrs
     Readonly array.  The attributes supported by zsh/curses; available
     as soon as the module is loaded.

zcurses_colors
     Readonly array.  The colors supported by zsh/curses; available as
     soon as the module is loaded.

zcurses_keycodes
     Readonly array.  The values that may be returned in the second
     parameter supplied to `zcurses input' in the order in which they
     are defined internally by curses.  Not all function keys are
     listed, only F0; curses reserves space for F0 up to F63.

zcurses_windows
     Readonly array.  The current list of windows, i.e. all windows that
     have been created with `zcurses addwin' and not removed with
     `zcurses delwin'.


File: zsh.info,  Node: The zsh/datetime Module,  Next: The zsh/deltochar Module,  Prev: The zsh/curses Module,  Up: Zsh Modules

22.10 The zsh/datetime Module
=============================



   The zsh/datetime module makes available one builtin command:


strftime [ -s SCALAR ] FORMAT EPOCHTIME
strftime -r [ -q ] [ -s SCALAR ] FORMAT TIMESTRING
     Output the date denoted by EPOCHTIME in the FORMAT specified.

     With the option -r (reverse), use the format FORMAT to parse the
     input string TIMESTRING and output the number of seconds since the
     epoch at which the time occurred.  If no timezone is parsed, the
     current timezone is used; other parameters are set to zero if not
     present.  If TIMESTRING does not match FORMAT the command returns
     status 1; it will additionally print an error message unless the
     option -q (quiet) is given.  If TIMESTRING matches FORMAT but not
     all characters in TIMESTRING were used, the conversion succeeds;
     however, a warning is issued unless the option -q is given.  The
     matching is implemented by the system function strptime; see man
     page strptime(3).  This means that zsh format extensions are not
     available, however for reverse lookup they are not required.  If
     the function is not implemented, the command returns status 2 and
     (unless -q is given) prints a message.

     If -s SCALAR is given, assign the date string (or epoch time in
     seconds if -r is given) to SCALAR instead of printing it.


The zsh/datetime module makes available one parameter:


EPOCHSECONDS
     An integer value representing the number of seconds since the
     epoch.


File: zsh.info,  Node: The zsh/deltochar Module,  Next: The zsh/example Module,  Prev: The zsh/datetime Module,  Up: Zsh Modules

22.11 The zsh/deltochar Module
==============================



   The zsh/deltochar module makes available two ZLE functions:


delete-to-char
     Read a character from the keyboard, and delete from the cursor
     position up to and including the next (or, with repeat count N,
     the Nth) instance of that character.  Negative repeat counts mean
     delete backwards.

zap-to-char
     This behaves like delete-to-char, except that the final occurrence
     of the character itself is not deleted.


File: zsh.info,  Node: The zsh/example Module,  Next: The zsh/files Module,  Prev: The zsh/deltochar Module,  Up: Zsh Modules

22.12 The zsh/example Module
============================



   The zsh/example module makes available one builtin command:


example [ -flags ] [ ARGS ... ]
     Displays the flags and arguments it is invoked with.


The purpose of the module is to serve as an example of how to write a
module.

File: zsh.info,  Node: The zsh/files Module,  Next: The zsh/mapfile Module,  Prev: The zsh/example Module,  Up: Zsh Modules

22.13 The zsh/files Module
==========================



   The zsh/files module makes available some common commands for file
manipulation as builtins; these commands are probably not needed for
many normal situations but can be useful in emergency recovery
situations with constrained resources.  The commands do not implement
all features now required by relevant standards committees.

For all commands, a variant beginning zf_ is also available and loaded
automatically.  Using the features capability of zmodload will let you
load only those names you want.

The commands loaded by default are:


chgrp [ -hRs ] GROUP FILENAME ...
     Changes group of files specified.  This is equivalent to chown with
     a USER-SPEC argument of `:GROUP'.

chown [ -hRs ] USER-SPEC FILENAME ...
     Changes ownership and group of files specified.

     The USER-SPEC can be in four forms:


    USER
          change owner to USER; do not change group

    USER::
          change owner to USER; do not change group

    USER:
          change owner to USER; change group to USER's primary group

    USER:GROUP
          change owner to USER; change group to GROUP

    :GROUP
          do not change owner; change group to GROUP

     In each case, the `:' may instead be a `.'.  The rule is that if
     there is a `:' then the separator is `:', otherwise if there is a
     `.' then the separator is `.', otherwise there is no separator.

     Each of USER and GROUP may be either a username (or group name, as
     appropriate) or a decimal user ID (group ID).  Interpretation as a
     name takes precedence, if there is an all-numeric username (or
     group name).

     If the target is a symbolic link, the -h option causes chown to set
     the ownership of the link instead of its target.

     The -R option causes chown to recursively descend into directories,
     changing the ownership of all files in the directory after
     changing the ownership of the directory itself.

     The -s option is a zsh extension to chown functionality.  It
     enables paranoid behaviour, intended to avoid security problems
     involving a chown being tricked into affecting files other than
     the ones intended.  It will refuse to follow symbolic links, so
     that (for example) ``chown luser /tmp/foo/passwd'' can't
     accidentally chown /etc/passwd if /tmp/foo happens to be a link to
     /etc.  It will also check where it is after leaving directories,
     so that a recursive chown of a deep directory tree can't end up
     recursively chowning /usr as a result of directories being moved
     up the tree.

ln [ -dfhins ] FILENAME DEST
ln [ -dfhins ] FILENAME ... DIR
     Creates hard (or, with -s, symbolic) links.  In the first form, the
     specified DESTination is created, as a link to the specified
     FILENAME.  In the second form, each of the FILENAMEs is taken in
     turn, and linked to a pathname in the specified DIRectory that has
     the same last pathname component.

     Normally, ln will not attempt to create hard links to directories.
     This check can be overridden using the -d option.  Typically only
     the super-user can actually succeed in creating hard links to
     directories.  This does not apply to symbolic links in any case.

     By default, existing files cannot be replaced by links.  The -i
     option causes the user to be queried about replacing existing
     files.  The -f option causes existing files to be silently
     deleted, without querying.  -f takes precedence.

     The -h and -n options are identical and both exist for
     compatibility; either one indicates that if the target is a symlink
     then it should not be dereferenced.  Typically this is used in
     combination with -sf so that if an existing link points to a
     directory then it will be removed, instead of followed.  If this
     option is used with multiple filenames and the target is a
     symbolic link pointing to a directory then the result is an error.

mkdir [ -p ] [ -m MODE ] DIR ...
     Creates directories.  With the -p option, non-existing parent
     directories are first created if necessary, and there will be no
     complaint if the directory already exists.  The -m option can be
     used to specify (in octal) a set of file permissions for the
     created directories, otherwise mode 777 modified by the current
     umask (see man page umask(2)) is used.

mv [ -fi ] FILENAME DEST
mv [ -fi ] FILENAME ... DIR
     Moves files.  In the first form, the specified FILENAME is moved
     to the specified DESTination.  In the second form, each of the
     FILENAMEs is taken in turn, and moved to a pathname in the
     specified DIRectory that has the same last pathname component.

     By default, the user will be queried before replacing any file
     that the user cannot write to, but writable files will be silently
     removed.  The -i option causes the user to be queried about
     replacing any existing files.  The -f option causes any existing
     files to be silently deleted, without querying.  -f takes
     precedence.

     Note that this mv will not move files across devices.  Historical
     versions of mv, when actual renaming is impossible, fall back on
     copying and removing files; if this behaviour is desired, use cp
     and rm manually.  This may change in a future version.

rm [ -dfirs ] FILENAME ...
     Removes files and directories specified.

     Normally, rm will not remove directories (except with the -r
     option).  The -d option causes rm to try removing directories with
     unlink (see man page unlink(2)), the same method used for files.
     Typically only the super-user can actually succeed in unlinking
     directories in this way.  -d takes precedence over -r.

     By default, the user will be queried before removing any file that
     the user cannot write to, but writable files will be silently
     removed.  The -i option causes the user to be queried about
     removing any files.  The -f option causes files to be silently
     deleted, without querying, and suppresses all error indications.
     -f takes precedence.

     The -r option causes rm to recursively descend into directories,
     deleting all files in the directory before removing the directory
     with the rmdir system call (see man page rmdir(2)).

     The -s option is a zsh extension to rm functionality.  It enables
     paranoid behaviour, intended to avoid common security problems
     involving a root-run rm being tricked into removing files other
     than the ones intended.  It will refuse to follow symbolic links,
     so that (for example) ``rm /tmp/foo/passwd'' can't accidentally
     remove /etc/passwd if /tmp/foo happens to be a link to /etc.  It
     will also check where it is after leaving directories, so that a
     recursive removal of a deep directory tree can't end up
     recursively removing /usr as a result of directories being moved
     up the tree.

rmdir DIR ...
     Removes empty directories specified.

sync
     Calls the system call of the same name (see man page sync(2)),
     which flushes dirty buffers to disk.  It might return before the
     I/O has actually been completed.


File: zsh.info,  Node: The zsh/mapfile Module,  Next: The zsh/mathfunc Module,  Prev: The zsh/files Module,  Up: Zsh Modules

22.14 The zsh/mapfile Module
============================



   The zsh/mapfile module provides one special associative array
parameter of the same name.


mapfile
     This associative array takes as keys the names of files; the
     resulting value is the content of the file.  The value is treated
     identically to any other text coming from a parameter.  The value
     may also be assigned to, in which case the file in question is
     written (whether or not it originally existed); or an element may
     be unset, which will delete the file in question.  For example,
     `vared mapfile[myfile]' works as expected, editing the file
     `myfile'.

     When the array is accessed as a whole, the keys are the names of
     files in the current directory, and the values are empty (to save
     a huge overhead in memory).  Thus ${(k)mapfile} has the same
     affect as the glob operator *(D), since files beginning with a dot
     are not special.  Care must be taken with expressions such as rm
     ${(k)mapfile}, which will delete every file in the current
     directory without the usual `rm *' test.

     The parameter mapfile may be made read-only; in that case, files
     referenced may not be written or deleted.

     A file may conveniently be read into an array as one line per
     element with the form `ARRAY=("${(f)mapfile[FILENAME]}")'.  The
     double quotes are necessary to prevent empty lines from being
     removed.



22.14.1 Limitations
-------------------

Although reading and writing of the file in question is efficiently
handled, zsh's internal memory management may be arbitrarily baroque;
however, mapfile is usually very much more efficient than anything
involving a loop.  Note in particular that the whole contents of the
file will always reside physically in memory when accessed (possibly
multiple times, due to standard parameter substitution operations).  In
particular, this means handling of sufficiently long files (greater
than the machine's swap space, or than the range of the pointer type)
will be incorrect.

No errors are printed or flagged for non-existent, unreadable, or
unwritable files, as the parameter mechanism is too low in the shell
execution hierarchy to make this convenient.

It is unfortunate that the mechanism for loading modules does not yet
allow the user to specify the name of the shell parameter to be given
the special behaviour.

File: zsh.info,  Node: The zsh/mathfunc Module,  Next: The zsh/newuser Module,  Prev: The zsh/mapfile Module,  Up: Zsh Modules

22.15 The zsh/mathfunc Module
=============================



   The zsh/mathfunc module provides standard mathematical functions for
use when evaluating mathematical formulae.  The syntax agrees with
normal C and FORTRAN conventions, for example,


     (( f = sin(0.3) ))

assigns the sine of 0.3 to the parameter f.

Most functions take floating point arguments and return a floating point
value.  However, any necessary conversions from or to integer type will
be performed automatically by the shell.  Apart from atan with a second
argument and the abs, int and float functions, all functions behave as
noted in the manual page for the corresponding C function, except that
any arguments out of range for the function in question will be
detected by the shell and an error reported.

The following functions take a single floating point argument: acos,
acosh, asin, asinh, atan, atanh, cbrt, ceil, cos, cosh, erf, erfc, exp,
expm1, fabs, floor, gamma, j0, j1, lgamma, log, log10, log1p, logb,
sin, sinh, sqrt, tan, tanh, y0, y1.  The atan function can optionally
take a second argument, in which case it behaves like the C function
atan2.  The ilogb function takes a single floating point argument, but
returns an integer.

The function signgam takes no arguments, and returns an integer, which
is the C variable of the same name, as described in man page gamma(3).
Note that it is therefore only useful immediately after a call to gamma
or lgamma.  Note also that `signgam(RPAR' and `signgam' are distinct
expressions.

The following functions take two floating point arguments: copysign,
fmod, hypot, nextafter.

The following take an integer first argument and a floating point second
argument: jn, yn.

The following take a floating point first argument and an integer second
argument: ldexp, scalb.

The function abs does not convert the type of its single argument; it
returns the absolute value of either a floating point number or an
integer.  The functions float and int convert their arguments into a
floating point or integer value (by truncation) respectively.

Note that the C pow function is available in ordinary math evaluation
as the `**' operator and is not provided here.

The function rand48 is available if your system's mathematical library
has the function erand48(3).  It returns a pseudo-random floating point
number between 0 and 1.  It takes a single string optional argument.

If the argument is not present, the random number seed is initialised by
three calls to the rand(3) function -- this produces the same random
numbers as the next three values of $RANDOM.

If the argument is present, it gives the name of a scalar parameter
where the current random number seed will be stored.  On the first
call, the value must contain at least twelve hexadecimal digits (the
remainder of the string is ignored), or the seed will be initialised in
the same manner as for a call to rand48 with no argument.  Subsequent
calls to rand48(PARAM) will then maintain the seed in the parameter
PARAM as a string of twelve hexadecimal digits, with no base signifier.
The random number sequences for different parameters are completely
independent, and are also independent from that used by calls to rand48
with no argument.

For example, consider


     print $(( rand48(seed) ))
     print $(( rand48() ))
     print $(( rand48(seed) ))

Assuming $seed does not exist, it will be initialised by the first
call.  In the second call, the default seed is initialised; note,
however, that because of the properties of rand() there is a
correlation between the seeds used for the two initialisations, so for
more secure uses, you should generate your own 12-byte seed.  The third
call returns to the same sequence of random numbers used in the first
call, unaffected by the intervening rand48().

File: zsh.info,  Node: The zsh/newuser Module,  Next: The zsh/parameter Module,  Prev: The zsh/mathfunc Module,  Up: Zsh Modules

22.16 The zsh/newuser Module
============================



   The zsh/newuser module is loaded at boot if it is available, the RCS
option is set, and the PRIVILEGED option is not set (all three are true
by default).  This takes place immediately after commands in the global
zshenv file (typically /etc/zshenv), if any, have been executed.  If
the module is not available it is silently ignored by the shell; the
module may safely be removed from $MODULE_PATH by the administrator if
it is not required.

On loading, the module tests if any of the start-up files .zshenv,
.zprofile, .zshrc or .zlogin exist in the directory given by the
environment variable ZDOTDIR, or the user's home directory if that is
not set.  The test is not performed and the module halts processing if
the shell was in an emulation mode (i.e. had been invoked as some other
shell than zsh).

If none of the start-up files were found, the module then looks for the
file newuser first in a sitewide directory, usually the parent
directory of the site-functions directory, and if that is not found the
module searches in a version-specific directory, usually the parent of
the functions directory containing version-specific functions.  (These
directories can be configured when zsh is built using the
-enable-site-scriptdir=DIR and -enable-scriptdir=DIR flags to
configure, respectively; the defaults are PREFIX/share/zsh and
PREFIX/share/zsh/$ZSH_VERSION where the default PREFIX is /usr/local.)

If the file newuser is found, it is then sourced in the same manner as
a start-up file.  The file is expected to contain code to install
start-up files for the user, however any valid shell code will be
executed.

The zsh/newuser module is then unconditionally unloaded.

Note that it is possible to achieve exactly the same effect as the
zsh/newuser module by adding code to /etc/zshenv.  The module exists
simply to allow the shell to make arrangements for new users without
the need for intervention by package maintainers and system
administrators.

The script supplied with the module invokes the shell function
zsh-newuser-install.  This may be invoked directly by the user even if
the zsh/newuser module is disabled.  Note, however, that if the module
is not installed the function will not be installed either.  The
function is documented in *note User Configuration Functions::.

File: zsh.info,  Node: The zsh/parameter Module,  Next: The zsh/pcre Module,  Prev: The zsh/newuser Module,  Up: Zsh Modules

22.17 The zsh/parameter Module
==============================



   The zsh/parameter module gives access to some of the internal hash
tables used by the shell by defining some special parameters.


options
     The keys for this associative array are the names of the options
     that can be set and unset using the setopt and unsetopt builtins.
     The value of each key is either the string on if the option is
     currently set, or the string off if the option is unset.  Setting
     a key to one of these strings is like setting or unsetting the
     option, respectively. Unsetting a key in this array is like
     setting it to the value off.

commands
     This array gives access to the command hash table. The keys are the
     names of external commands, the values are the pathnames of the
     files that would be executed when the command would be invoked.
     Setting a key in this array defines a new entry in this table in
     the same way as with the hash builtin. Unsetting a key as in `unset
     "commands[foo]"' removes the entry for the given key from the
     command hash table.

functions
     This associative array maps names of enabled functions to their
     definitions. Setting a key in it is like defining a function with
     the name given by the key and the body given by the value.
     Unsetting a key removes the definition for the function named by
     the key.

dis_functions
     Like functions but for disabled functions.

builtins
     This associative array gives information about the builtin commands
     currently enabled. The keys are the names of the builtin commands
     and the values are either `undefined' for builtin commands that
     will automatically be loaded from a module if invoked or `defined'
     for builtin commands that are already loaded.

dis_builtins
     Like builtins but for disabled builtin commands.

reswords
     This array contains the enabled reserved words.

dis_reswords
     Like reswords but for disabled reserved words.

aliases
     This maps the names of the regular aliases currently enabled to
     their expansions.

dis_aliases
     Like aliases but for disabled regular aliases.

galiases
     Like aliases, but for global aliases.

dis_galiases
     Like galiases but for disabled global aliases.

saliases
     Like raliases, but for suffix aliases.

dis_saliases
     Like saliases but for disabled suffix aliases.

parameters
     The keys in this associative array are the names of the parameters
     currently defined. The values are strings describing the type of
     the parameter, in the same format used by the t parameter flag, see
     *note Parameter Expansion:: .  Setting or unsetting keys in this
     array is not possible.

modules
     An associative array giving information about modules. The keys
     are the names of the modules loaded, registered to be autoloaded,
     or aliased. The value says which state the named module is in and
     is one of the strings `loaded', `autoloaded', or `alias:NAME',
     where NAME is the name the module is aliased to.

     Setting or unsetting keys in this array is not possible.

dirstack
     A normal array holding the elements of the directory stack. Note
     that the output of the dirs builtin command includes one more
     directory, the current working directory.

history
     This associative array maps history event numbers to the full
     history lines.

historywords
     A special array containing the words stored in the history.

jobdirs
     This associative array maps job numbers to the directories from
     which the job was started (which may not be the current directory
     of the job).

     The keys of the associative arrays are usually valid job numbers,
     and these are the values output with, for example, ${(k)jobdirs}.
     Non-numeric job references may be used when looking up a value;
     for example, ${jobdirs[%+]} refers to the current job.

jobtexts
     This associative array maps job numbers to the texts of the
     command lines that were used to start the jobs.

     Handling of the keys of the associative array is as described for
     jobdirs above.

jobstates
     This associative array gives information about the states of the
     jobs currently known. The keys are the job numbers and the values
     are strings of the form `JOB-STATE:MARK:PID=STATE...'. The
     JOB-STATE gives the state the whole job is currently in, one of
     `running', `suspended', or `done'. The MARK is `+' for the current
     job, `-' for the previous job and empty otherwise. This is
     followed by one `PID=STATE' for every process in the job. The PIDs
     are, of course, the process IDs and the STATE describes the state
     of that process.

     Handling of the keys of the associative array is as described for
     jobdirs above.

nameddirs
     This associative array maps the names of named directories to the
     pathnames they stand for.

userdirs
     This associative array maps user names to the pathnames of their
     home directories.

funcfiletrace
     This array contains the absolute line numbers and corresponding
     file names for the point where the current function, sourced file,
     or (if EVAL_LINENO is set) eval command was called.  The array is
     of the same length as funcsourcetrace and functrace, but differs
     from funcsourcetrace in that the line and file are the point of
     call, not the point of definition, and differs from functrace in
     that all values are absolute line numbers in files, rather than
     relative to the start of a function, if any.

funcsourcetrace
     This array contains the file names and line numbers of the points
     where the functions, sourced files, and (if EVAL_LINENO is set)
     eval commands currently being executed were defined.  The line
     number is the line where the `function NAME' or `NAME ()' started.
     In the case of an autoloaded function  the line number is reported
     as zero.  The format of each element is FILENAME:LINENO.  For
     functions autoloaded from a file in native zsh format, where only
     the body of the function occurs in the file, or for files that
     have been executed by the source or `.' builtins, the trace
     information is shown as FILENAME:0, since the entire file is the
     definition.

     Most users will be interested in the information in the
     funcfiletrace array instead.

funcstack
     This array contains the names of the functions, sourced files, and
     (if EVAL_LINENO is set) eval commands. currently being executed.
     The first element is the name of the function using the parameter.

functrace
     This array contains the names and line numbers of the callers
     corresponding to the functions currently being executed.  The
     format of each element is NAME:LINENO.  Callers are also shown for
     sourced files; the caller is the point where the source or `.'
     command was executed.


File: zsh.info,  Node: The zsh/pcre Module,  Next: The zsh/regex Module,  Prev: The zsh/parameter Module,  Up: Zsh Modules

22.18 The zsh/pcre Module
=========================



   The zsh/pcre module makes some commands available as builtins:


pcre_compile [ -aimxs ] PCRE
     Compiles a perl-compatible regular expression.

     Option -a will force the pattern to be anchored.  Option -i will
     compile a case-insensitive pattern.  Option -m will compile a
     multi-line pattern; that is, ^ and $ will match newlines within
     the pattern.  Option -x will compile an extended pattern, wherein
     whitespace and # comments are ignored.  Option -s makes the dot
     metacharacter match all characters, including those that indicate
     newline.

pcre_study
     Studies the previously-compiled PCRE which may result in faster
     matching.

pcre_match [ -v VAR ] [ -a ARR ] [ -n OFFSET ] [ -b ] STRING
     Returns successfully if string matches the previously-compiled
     PCRE.

     Upon successful match, if the expression captures substrings
     within parentheses, pcre_match will set the array $MATCH to those
     substrings, unless the -a option is given, in which case it will
     set the array ARR.  Similarly, the variable MATCH will be set to
     the entire matched portion of the string, unless the -v option is
     given, in which case the variable VAR will be set.  No variables
     are altered if there is no successful match.  A -n option starts
     searching for a match from the byte OFFSET position in STRING.  If
     the -b option is given, the variable ZPCRE_OP will be set to an
     offset pair string, representing the byte offset positions of the
     entire matched portion within the STRING.  For example, a ZPCRE_OP
     set to "32 45" indicates that the matched portion began on byte
     offset 32 and ended on byte offset 44.  Here, byte offset position
     45 is the position directly after the matched portion.  Keep in
     mind that the byte position isn't necessarily the same as the
     character position when UTF-8 characters are involved.
     Consequently, the byte offset positions are only to be relied on
     in the context of using them for subsequent searches on STRING,
     using an offset position as an argument to the -n option.  This is
     mostly used to implement the "find all non-overlapping matches"
     functionality.

     A simple example of "find all non-overlapping matches":



          string="The following zip codes: 78884 90210 99513"
          pcre_compile -m "\d{5}"
          accum=()
          pcre_match -b -- $string
          while [[ $? -eq 0 ]] do
              b=($=ZPCRE_OP)
              accum+=$MATCH
              pcre_match -b -n $b[2] -- $string
          done
          print -l $accum


The zsh/pcre module makes available the following test condition:
expr -pcre-match pcre
     Matches a string against a perl-compatible regular expression.

     For example,

     [[ "$text" -pcre-match ^d+$ ]] && print text variable contains
     only "d's".


File: zsh.info,  Node: The zsh/regex Module,  Next: The zsh/sched Module,  Prev: The zsh/pcre Module,  Up: Zsh Modules

22.19 The zsh/regex Module
==========================



   The zsh/regex module makes available the following test condition:
EXPR -regex-match REGEX
     Matches a string against a POSIX extended regular expression.  On
     successful match, matched portion of the string will normally be
     placed in the MATCH variable.  If there are any capturing
     parentheses within the regex, then the match array variable will
     contain those.  If the match is not successful, then the variables
     will not be altered.

     For example,


          [[ alphabetical -regex-match ^a([^a]+)a([^a]+)a ]] &&
          print -l $MATCH X $match

     If the option REMATCH_PCRE is not set, then the =~ operator will
     automatically load this module as needed and will invoke the
     -regex-match operator.

     If BASH_REMATCH is set, then the array BASH_REMATCH will be set
     instead of MATCH and match.


File: zsh.info,  Node: The zsh/sched Module,  Next: The zsh/net/socket Module,  Prev: The zsh/regex Module,  Up: Zsh Modules

22.20 The zsh/sched Module
==========================



   The zsh/sched module makes available one builtin command and one
parameter.


sched [-o] [+]HH:MM[:SS] COMMAND ...
sched [-o] [+]SECONDS COMMAND ...
sched [ -ITEM ]
     Make an entry in the scheduled list of commands to execute.  The
     time may be specified in either absolute or relative time, and
     either as hours, minutes and (optionally) seconds separated by a
     colon, or seconds alone.  An absolute number of seconds indicates
     the time since the epoch (1970/01/01 00:00); this is useful in
     combination with the features in the zsh/datetime module, see
     *note The zsh/datetime Module::.

     With no arguments, prints the list of scheduled commands.  If the
     scheduled command has the -o flag set, this is shown at the start
     of the command.

     With the argument `-ITEM', removes the given item from the list.
     The numbering of the list is continuous and entries are in time
     order, so the numbering can change when entries are added or
     deleted.

     Commands are executed either immediately before a prompt, or while
     the shell's line editor is waiting for input.  In the latter case
     it is useful to be able to produce output that does not interfere
     with the line being edited.  Providing the option -o causes the
     shell to clear the command line before the event and redraw it
     afterwards.  This should be used with any scheduled event that
     produces visible output to the terminal; it is not needed, for
     example, with output that updates a terminal emulator's title bar.



zsh_scheduled_events
     A readonly array corresponding to the events scheduled by the
     sched builtin.  The indices of the array correspond to the numbers
     shown when sched is run with no arguments (provided that the
     KSH_ARRAYS option is not set).  The value of the array consists of
     the scheduled time in seconds since the epoch (see The
     zsh/datetime Module for facilities for using this number),
     followed by a colon, followed by any options (which may be empty
     but will be preceded by a `-' otherwise), followed by a colon,
     followed by the command to be executed.

     The sched builtin should be used for manipulating the events.  Note
     that this will have an immediate effect on the contents of the
     array, so that indices may become invalid.


File: zsh.info,  Node: The zsh/net/socket Module,  Next: The zsh/stat Module,  Prev: The zsh/sched Module,  Up: Zsh Modules

22.21 The zsh/net/socket Module
===============================



   The zsh/net/socket module makes available one builtin command:


zsocket [ -altv ] [ -d FD ] [ ARGS ]
     zsocket is implemented as a builtin to allow full use of shell
     command line editing, file I/O, and job control mechanisms.



22.21.1 Outbound Connections
----------------------------




zsocket [ -v ] [ -d FD ] FILENAME
     Open a new Unix domain connection to FILENAME.  The shell
     parameter REPLY will be set to the file descriptor associated with
     that connection.  Currently, only stream connections are supported.

     If -d is specified, its argument will be taken as the target file
     descriptor for the connection.

     In order to elicit more verbose output, use -v.



22.21.2 Inbound Connections
---------------------------




zsocket -l [ -v ] [ -d FD ] FILENAME
     zsocket -l will open a socket listening on FILENAME.  The shell
     parameter REPLY will be set to the file descriptor associated with
     that listener.

     If -d is specified, its argument will be taken as the target file
     descriptor for the connection.

     In order to elicit more verbose output, use -v.

zsocket -a [ -tv ] [ -d TARGETFD ] LISTENFD
     zsocket -a will accept an incoming connection to the socket
     associated with LISTENFD.  The shell parameter REPLY will be set
     to the file descriptor associated with the inbound connection.

     If -d is specified, its argument will be taken as the target file
     descriptor for the connection.

     If -t is specified, zsocket will return if no incoming connection
     is pending.  Otherwise it will wait for one.

     In order to elicit more verbose output, use -v.


File: zsh.info,  Node: The zsh/stat Module,  Next: The zsh/system Module,  Prev: The zsh/net/socket Module,  Up: Zsh Modules

22.22 The zsh/stat Module
=========================



   The zsh/stat module makes available one builtin command under two
possible names:


zstat [ -gnNolLtTrs ] [ -f FD ] [ -H HASH ] [ -A ARRAY ] [ -F FMT ] [ +ELEMENT ] [ FILE ... ]
stat ...
     The command acts as a front end to the stat system call (see man
     page stat(2)).  The same command is provided with two names; as
     the name stat is often used by an external command it is
     recommended that only the zstat form of the command is used.  This
     can be arranged by loading the module with the command `zmodload
     -F zsh/stat b:zstat'.

     If the stat call fails, the appropriate system error message
     printed and status 1 is returned.  The fields of struct stat give
     information about the files provided as arguments to the command.
     In addition to those available from the stat call, an extra
     element `link' is provided.  These elements are:


    device
          The number of the device on which the file resides.

    inode
          The unique number of the file on this device (`_inode_'
          number).

    mode
          The mode of the file; that is, the file's type and access
          permissions.  With the -s option, this will be returned as a
          string corresponding to the first column in the display of
          the ls -l command.

    nlink
          The number of hard links to the file.

    uid
          The user ID of the owner of the file.  With the -s option,
          this is displayed as a user name.

    gid
          The group ID of the file.  With the -s option, this is
          displayed as a group name.

    rdev
          The raw device number.  This is only useful for special
          devices.

    size
          The size of the file in bytes.

    atime
    mtime
    ctime
          The last access, modification and inode change times of the
          file, respectively, as the number of seconds since midnight
          GMT on 1st January, 1970.  With the -s option, these are
          printed as strings for the local time zone; the format can be
          altered with the -F option, and with the -g option the times
          are in GMT.

    blksize
          The number of bytes in one allocation block on the device on
          which the file resides.

    block
          The number of disk blocks used by the file.

    link
          If the file is a link and the -L option is in effect, this
          contains the name of the file linked to, otherwise it is
          empty.  Note that if this element is selected (``zstat
          +link'') then the -L option is automatically used.


     A particular element may be selected by including its name
     preceded by a `+' in the option list; only one element is allowed.
     The element may be shortened to any unique set of leading
     characters.  Otherwise, all elements will be shown for all files.

     Options:


    -A ARRAY
          Instead of displaying the results on standard output, assign
          them to an ARRAY, one struct stat element per array element
          for each file in order.  In this case neither the name of the
          element nor the name of the files appears in ARRAY unless the
          -t or -n options were given, respectively.  If -t is given,
          the element name appears as a prefix to the appropriate array
          element; if -n is given, the file name appears as a separate
          array element preceding all the others.  Other formatting
          options are respected.

    -H HASH
          Similar to -A, but instead assign the values to HASH.  The
          keys are the elements listed above.  If the -n option is
          provided then the name of the file is included in the hash
          with key name.

    -f FD
          Use the file on file descriptor FD instead of named files; no
          list of file names is allowed in this case.

    -F FMT
          Supplies a strftime (see man page strftime(3)) string for the
          formatting of the time elements.  The -s option is implied.

    -g
          Show the time elements in the GMT time zone.  The -s option
          is implied.

    -l
          List the names of the type elements (to standard output or an
          array as appropriate) and return immediately; options other
          than -A and arguments are ignored.

    -L
          Perform an lstat (see man page lstat(2)) rather than a stat
          system call.  In this case, if the file is a link, information
          about the link itself rather than the target file is returned.
          This option is required to make the link element useful.
          It's important to note that this is the exact opposite from
          man page ls(1), etc.

    -n
          Always show the names of files.  Usually these are only shown
          when output is to standard output and there is more than one
          file in the list.

    -N
          Never show the names of files.

    -o
          If a raw file mode is printed, show it in octal, which is
          more useful for human consumption than the default of
          decimal.  A leading zero will be printed in this case.  Note
          that this does not affect whether a raw or formatted file
          mode is shown, which is controlled by the -r and -s options,
          nor whether a mode is shown at all.

    -r
          Print raw data (the default format) alongside string data
          (the -s format); the string data appears in parentheses after
          the raw data.

    -s
          Print mode, uid, gid and the three time elements as strings
          instead of numbers.  In each case the format is like that of
          ls -l.

    -t
          Always show the type names for the elements of struct stat.
          Usually these are only shown when output is to standard
          output and no individual element has been selected.

    -T
          Never show the type names of the struct stat elements.



File: zsh.info,  Node: The zsh/system Module,  Next: The zsh/net/tcp Module,  Prev: The zsh/stat Module,  Up: Zsh Modules

22.23 The zsh/system Module
===========================



   The zsh/system module makes available various builtin commands and
parameters.



22.23.1 Builtins
----------------


syserror [ -e ERRVAR ] [ -p PREFIX ] [ ERRNO | ERRNAME ]
     This command prints out the error message associated with ERRNO, a
     system error number, followed by a newline to standard error.

     Instead of the error number, a name ERRNAME, for example ENOENT,
     may be used.  The set of names is the same as the contents of the
     array errnos, see below.

     If the string PREFIX is given, it is printed in front of the error
     message, with no intervening space.

     If ERRVAR is supplied, the entire message, without a newline, is
     assigned to the parameter names ERRVAR and nothing is output.

     A return status of 0 indicates the message was successfully printed
     (although it may not be useful if the error number was out of the
     system's range), a return status of 1 indicates an error in the
     parameters, and a return status of 2 indicates the error name was
     not recognised (no message is printed for this).

sysread [ -c COUNTVAR ] [ -i INFD ] [ -o OUTFD ]
[ -s BUFSIZE ] [ -t TIMEOUT ] [ PARAM ]
     Perform a single system read from file descriptor INFD, or zero if
     that is not given.  The result of the read is stored in PARAM or
     REPLY if that is not given.  If COUNTVAR is given, the number of
     bytes read is assigned to the parameter named by COUNTVAR.

     The maximum number of bytes read is BUFSIZE or 8192 if that is not
     given, however the command returns as soon as any number of bytes
     was successfully read.

     If TIMEOUT is given, it specifies a timeout in seconds, which may
     be zero to poll the file descriptor.  This is handled by the poll
     system call if available, otherwise the select system call if
     available.

     If OUTFD is given, an attempt is made to write all the bytes just
     read to the file descriptor OUTFD.  If this fails, because of a
     system error other than EINTR or because of an internal zsh error
     during an interrupt, the bytes read but not written are stored in
     the parameter named by PARAM if supplied (no default is used in
     this case), and the number of bytes read but not written is stored
     in the parameter named by COUNTVAR if that is supplied.  If it was
     successful, COUNTVAR contains the full number of bytes transferred,
     as usual, and PARAM is not set.

     The error EINTR (interrupted system call) is handled internally so
     that shell interrupts are transparent to the caller.  Any other
     error causes a return.

     The possible return statuses are
    0
          At least one byte of data was successfully read and, if
          appropriate, written.

    1
          There was an error in the parameters to the command.  This is
          the only error for which a message is printed to standard
          error.

    2
          There was an error on the read, or on polling the input file
          descriptor for a timeout.  The parameter ERRNO gives the
          error.

    3
          Data were successfully read, but there was an error writing
          them to OUTFD.  The parameter ERRNO gives the error.

    4
          The attempt to read timed out.  Note this does not set ERRNO
          as this is not a system error.

    5
          No system error occurred, but zero bytes were read.  This
          usually indicates end of file.  The parameters are set
          according to the usual rules; no write to OUTFD is attempted.


syswrite [ -c COUNTVAR ] [ -o OUTFD ] DATA
     The data (a single string of bytes) are written to the file
     descriptor OUTFD, or 1 if that is not given, using the write
     system call.  Multiple write operations may be used if the first
     does not write all the data.

     If COUNTVAR is given, the number of byte written is stored in the
     parameter named by COUNTVAR; this may not be the full length of
     DATA if an error occurred.

     The error EINTR (interrupted system call) is handled internally by
     retrying; otherwise an error causes the command to return.  For
     example, if the file descriptor is set to non-blocking output, an
     error EAGAIN (on some systems, EWOULDBLOCK) may result in the
     command returning early.

     The return status may be 0 for success, 1 for an error in the
     parameters to the command, or 2 for an error on the write; no
     error message is printed in the last case, but the parameter ERRNO
     will reflect the error that occurred.

zsystem flock [ -t TIMEOUT ] [ -f VAR ] [-er] FILE
zsystem flock -u FD_EXPR
     The builtin zsystem's subcommand flock performs advisory file
     locking (via the man page fcntl(2) system call) over the entire
     contents of the given file.  This form of locking requires the
     processes accessing the file to cooperate; its most obvious use is
     between two instances of the shell itself.

     In the first form the named FILE, which must already exist, is
     locked by opening a file descriptor to the file and applying a
     lock to the file descriptor.  The lock terminates when the shell
     process that created the lock exits; it is therefore often
     convenient to create file locks within subshells, since the lock
     is automatically released when the subshell exits.  Status 0 is
     returned if the lock succeeds, else status 1.

     In the second form the file descriptor given by the arithmetic
     expression fd_expr is closed, releasing a lock.  The file
     descriptor can be queried by using the `-f VAR' form during the
     lock; on a successful lock, the shell variable VAR is set to the
     file descriptor used for locking.  The lock will be released if the
     file descriptor is closed by any other means, for example using
     `exec {VAR}>&-'; however, the form described here performs a
     safety check that the file descriptor is in use for file locking.

     By default the shell waits indefinitely for the lock to succeed.
     The option -t TIMEOUT specifies a timeout for the lock in seconds;
     currently this must be an integer.  The shell will attempt to lock
     the file once a second during this period.  If the attempt times
     out, status 2 is returned.

     If the option -e is given, the file descriptor for the lock is
     preserved when the shell uses exec to start a new process;
     otherwise it is closed at that point and the lock released.

     If the option -r is given, the lock is only for reading, otherwise
     it is for reading and writing.  The file descriptor is opened
     accordingly.

zsystem supports SUBCOMMAND
     The builtin zsystem's subcommand supports tests whether a given
     subcommand is supported.  It returns status 0 if so, else status
     1.  It operates silently unless there was a syntax error (i.e. the
     wrong number of arguments), in which case status 255 is returned.
     Status 1 can indicate one of two things:  SUBCOMMAND is known but
     not supported by the current operating system, or SUBCOMMAND is
     not known (possibly because this is an older version of the shell
     before it was implemented).



22.23.2 Parameters
------------------


errnos
     A readonly array of the names of errors defined on the system.
     These are typically macros defined in C by including the system
     header file errno.h.  The index of each name (assuming the option
     KSH_ARRAYS is unset) corresponds to the error number.  Error
     numbers NUM before the last known error which have no name are
     given the name ENUM in the array.

     Note that aliases for errors are not handled; only the canonical
     name is used.

sysparams
     A readonly associative array.  The keys are:
    pid
          Returns the process ID of the current process, even in
          subshells.  Compare $$, which returns the process ID of the
          main shell process.

    ppid
          Returns the process ID of the parent of the current process,
          even in subshells.  Compare $PPID, which returns the process
          ID of the parent of the main shell process.



File: zsh.info,  Node: The zsh/net/tcp Module,  Next: The zsh/termcap Module,  Prev: The zsh/system Module,  Up: Zsh Modules

22.24 The zsh/net/tcp Module
============================



   The zsh/net/tcp module makes available one builtin command:


ztcp [ -acflLtv ] [ -d FD ] [ ARGS ]
     ztcp is implemented as a builtin to allow full use of shell
     command line editing, file I/O, and job control mechanisms.

     If ztcp is run with no options, it will output the contents of its
     session table.

     If it is run with only the option -L, it will output the contents
     of the session table in a format suitable for automatic parsing.
     The option is ignored if given with a command to open or close a
     session.  The output consists of a set of lines, one per session,
     each containing the following elements separated by spaces:


    File descriptor
          The file descriptor in use for the connection.  For normal
          inbound (I) and outbound (O) connections this may be read and
          written by the usual shell mechanisms.  However, it should
          only be close with `ztcp -c'.

    Connection type
          A letter indicating how the session was created:


         Z
               A session created with the zftp command.

         L
               A connection opened for listening with `ztcp -l'.

         I
               An inbound connection accepted with `ztcp -a'.

         O
               An outbound connection created with `ztcp HOST ...'.



    The local host
          This is usually set to an all-zero IP address as the address
          of the localhost is irrelevant.

    The local port
          This is likely to be zero unless the connection is for
          listening.

    The remote host
          This is the fully qualified domain name of the peer, if
          available, else an IP address.  It is an all-zero IP address
          for a session opened for listening.

    The remote port
          This is zero for a connection opened for listening.




22.24.1 Outbound Connections
----------------------------




ztcp [ -v ] [ -d FD ] HOST [ PORT ]
     Open a new TCP connection to HOST.  If the PORT is omitted, it
     will default to port 23.  The connection will be added to the
     session table and the shell parameter REPLY will be set to the
     file descriptor associated with that connection.

     If -d is specified, its argument will be taken as the target file
     descriptor for the connection.

     In order to elicit more verbose output, use -v.



22.24.2 Inbound Connections
---------------------------




ztcp -l [ -v ] [ -d FD ] PORT
     ztcp -l will open a socket listening on TCP PORT.  The socket will
     be added to the session table and the shell parameter REPLY will
     be set to the file descriptor associated with that listener.

     If -d is specified, its argument will be taken as the target file
     descriptor for the connection.

     In order to elicit more verbose output, use -v.

ztcp -a [ -tv ] [ -d TARGETFD ] LISTENFD
     ztcp -a will accept an incoming connection to the port associated
     with LISTENFD.  The connection will be added to the session table
     and the shell parameter REPLY will be set to the file descriptor
     associated with the inbound connection.

     If -d is specified, its argument will be taken as the target file
     descriptor for the connection.

     If -t is specified, ztcp will return if no incoming connection is
     pending.  Otherwise it will wait for one.

     In order to elicit more verbose output, use -v.



22.24.3 Closing Connections
---------------------------




ztcp -cf [ -v ] [ FD ]
ztcp -c [ -v ] [ FD ]
     ztcp -c will close the socket associated with FD.  The socket will
     be removed from the session table.  If FD is not specified, ztcp
     will close everything in the session table.

     Normally, sockets registered by zftp (see *note The zsh/zftp
     Module:: ) cannot be closed this way.  In order to force such a
     socket closed, use -f.

     In order to elicit more verbose output, use -v.



22.24.4 Example
---------------

Here is how to create a TCP connection between two instances of zsh.  We
need to pick an unassigned port; here we use the randomly chosen 5123.

On host1,
     zmodload zsh/net/tcp
     ztcp -l 5123
     listenfd=$REPLY
     ztcp -a $listenfd
     fd=$REPLY
   The second from last command blocks until there is an incoming
connection.

Now create a connection from host2 (which may, of course, be the same
machine):
     zmodload zsh/net/tcp
     ztcp host1 5123
     fd=$REPLY

Now on each host, $fd contains a file descriptor for talking to the
other.  For example, on host1:
     print This is a message >&$fd
   and on host2:
     read -r line <&$fd; print -r - $line
   prints `This is a message'.

To tidy up, on host1:
     ztcp -c $listenfd
     ztcp -c $fd
   and on host2
     ztcp -c $fd

File: zsh.info,  Node: The zsh/termcap Module,  Next: The zsh/terminfo Module,  Prev: The zsh/net/tcp Module,  Up: Zsh Modules

22.25 The zsh/termcap Module
============================



   The zsh/termcap module makes available one builtin command:


echotc CAP [ ARG ... ]
     Output the termcap value corresponding to the capability CAP, with
     optional arguments.


The zsh/termcap module makes available one parameter:


termcap
     An associative array that maps termcap capability codes to their
     values.


File: zsh.info,  Node: The zsh/terminfo Module,  Next: The zsh/zftp Module,  Prev: The zsh/termcap Module,  Up: Zsh Modules

22.26 The zsh/terminfo Module
=============================



   The zsh/terminfo module makes available one builtin command:


echoti CAP [ ARG ]
     Output the terminfo value corresponding to the capability CAP,
     instantiated with ARG if applicable.


The zsh/terminfo module makes available one parameter:


terminfo
     An associative array that maps terminfo capability names to their
     values.


File: zsh.info,  Node: The zsh/zftp Module,  Next: The zsh/zle Module,  Prev: The zsh/terminfo Module,  Up: Zsh Modules

22.27 The zsh/zftp Module
=========================



   The zsh/zftp module makes available one builtin command:


zftp SUBCOMMAND [ ARGS ]
     The zsh/zftp module is a client for FTP (file transfer protocol).
     It is implemented as a builtin to allow full use of shell command
     line editing, file I/O, and job control mechanisms.  Often, users
     will access it via shell functions providing a more powerful
     interface; a set is provided with the zsh distribution and is
     described in *note Zftp Function System::.  However, the zftp
     command is entirely usable in its own right.

     All commands consist of the command name zftp followed by the name
     of a subcommand.  These are listed below.  The return status of
     each subcommand is supposed to reflect the success or failure of
     the remote operation.  See a description of the variable
     ZFTP_VERBOSE for more information on how responses from the server
     may be printed.



22.27.1 Subcommands
-------------------




open HOST[:PORT] [ USER [ PASSWORD [ ACCOUNT ] ] ]
     Open a new FTP session to HOST, which may be the name of a TCP/IP
     connected host or an IP number in the standard dot notation.  If
     the argument is in the form HOST:PORT, open a connection to TCP
     port PORT instead of the standard FTP port 21.  This may be the
     name of a TCP service or a number:  see the description of
     ZFTP_PORT below for more information.

     If IPv6 addresses in colon format are used, the HOST should be
     surrounded by quoted square brackets to distinguish it from the
     PORT, for example '[fe80::203:baff:fe02:8b56]'.  For consistency
     this is allowed with all forms of HOST.

     Remaining arguments are passed to the login subcommand.  Note that
     if no arguments beyond HOST are supplied, open will _not_
     automatically call login.  If no arguments at all are supplied,
     open will use the parameters set by the params subcommand.

     After a successful open, the shell variables ZFTP_HOST, ZFTP_PORT,
     ZFTP_IP and ZFTP_SYSTEM are available; see `Variables' below.

login [ NAME [ PASSWORD [ ACCOUNT ] ] ]
user [ NAME [ PASSWORD [ ACCOUNT ] ] ]
     Login the user NAME with parameters PASSWORD and ACCOUNT.  Any of
     the parameters can be omitted, and will be read from standard
     input if needed (NAME is always needed).  If standard input is a
     terminal, a prompt for each one will be printed on standard error
     and PASSWORD will not be echoed.  If any of the parameters are not
     used, a warning message is printed.

     After a successful login, the shell variables ZFTP_USER,
     ZFTP_ACCOUNT and ZFTP_PWD are available; see `Variables' below.

     This command may be re-issued when a user is already logged in, and
     the server will first be reinitialized for a new user.

params [ HOST [ USER [ PASSWORD [ ACCOUNT ] ] ] ]
params -
     Store the given parameters for a later open command with no
     arguments.  Only those given on the command line will be
     remembered.  If no arguments are given, the parameters currently
     set are printed, although the password will appear as a line of
     stars; the return status is one if no parameters were set, zero
     otherwise.

     Any of the parameters may be specified as a `?', which may need to
     be quoted to protect it from shell expansion.  In this case, the
     appropriate parameter will be read from stdin as with the login
     subcommand, including special handling of PASSWORD.  If the `?' is
     followed by a string, that is used as the prompt for reading the
     parameter instead of the default message (any necessary
     punctuation and whitespace should be included at the end of the
     prompt).  The first letter of the parameter (only) may be quoted
     with a `\'; hence an argument "\\$word" guarantees that the string
     from the shell parameter $word will be treated literally, whether
     or not it begins with a `?'.

     If instead a single `-' is given, the existing parameters, if any,
     are deleted.  In that case, calling open with no arguments will
     cause an error.

     The list of parameters is not deleted after a close, however it
     will be deleted if the zsh/zftp module is unloaded.

     For example,


          zftp params ftp.elsewhere.xx juser '?Password for juser: '

     will store the host ftp.elsewhere.xx and the user juser and then
     prompt the user for the corresponding password with the given
     prompt.

test
     Test the connection; if the server has reported that it has closed
     the connection (maybe due to a timeout), return status 2; if no
     connection was open anyway, return status 1; else return status 0.
     The test subcommand is silent, apart from messages printed by the
     $ZFTP_VERBOSE mechanism, or error messages if the connection
     closes.  There is no network overhead for this test.

     The test is only supported on systems with either the select(2) or
     poll(2) system calls; otherwise the message `not supported on this
     system' is printed instead.

     The test subcommand will automatically be called at the start of
     any other subcommand for the current session when a connection is
     open.

cd DIRECTORY
     Change the remote directory to DIRECTORY.  Also alters the shell
     variable ZFTP_PWD.

cdup
     Change the remote directory to the one higher in the directory
     tree.  Note that cd .. will also work correctly on non-UNIX
     systems.

dir [ ARGS... ]
     Give a (verbose) listing of the remote directory.  The ARGS are
     passed directly to the server. The command's behaviour is
     implementation dependent, but a UNIX server will typically
     interpret ARGS as arguments to the ls command and with no
     arguments return the result of `ls -l'. The directory is listed to
     standard output.

ls [ ARGS ]
     Give a (short) listing of the remote directory.  With no ARGS,
     produces a raw list of the files in the directory, one per line.
     Otherwise, up to vagaries of the server implementation, behaves
     similar to dir.

type [ TYPE ]
     Change the type for the transfer to TYPE, or print the current type
     if TYPE is absent.  The allowed values are `A' (ASCII), `I'
     (Image, i.e. binary), or `B' (a synonym for `I').

     The FTP default for a transfer is ASCII.  However, if zftp finds
     that the remote host is a UNIX machine with 8-bit byes, it will
     automatically switch to using binary for file transfers upon open.
     This can subsequently be overridden.

     The transfer type is only passed to the remote host when a data
     connection is established; this command involves no network
     overhead.

ascii
     The same as type A.

binary
     The same as type I.

mode [ S | B ]
     Set the mode type to stream (S) or block (B).  Stream mode is the
     default; block mode is not widely supported.

remote FILES...
local [ FILES... ]
     Print the size and last modification time of the remote or local
     files.  If there is more than one item on the list, the name of the
     file is printed first.  The first number is the file size, the
     second is the last modification time of the file in the format
     CCYYMMDDhhmmSS consisting of year, month, date, hour, minutes and
     seconds in GMT.  Note that this format, including the length, is
     guaranteed, so that time strings can be directly compared via the
     [[ builtin's < and > operators, even if they are too long to be
     represented as integers.

     Not all servers support the commands for retrieving this
     information.  In that case, the remote command will print nothing
     and return status 2, compared with status 1 for a file not found.

     The local command (but not remote) may be used with no arguments,
     in which case the information comes from examining file descriptor
     zero.  This is the same file as seen by a put command with no
     further redirection.

get FILE [...]
     Retrieve all FILEs from the server, concatenating them and sending
     them to standard output.

put FILE [...]
     For each FILE, read a file from standard input and send that to
     the remote host with the given name.

append FILE [...]
     As put, but if the remote FILE already exists, data is appended to
     it instead of overwriting it.

getat FILE POINT
putat FILE POINT
appendat FILE POINT
     Versions of get, put and append which will start the transfer at
     the given POINT in the remote FILE.  This is useful for appending
     to an incomplete local file.  However, note that this ability is
     not universally supported by servers (and is not quite the
     behaviour specified by the standard).

delete FILE [...]
     Delete the list of files on the server.

mkdir DIRECTORY
     Create a new directory DIRECTORY on the server.

rmdir DIRECTORY
     Delete the directory DIRECTORY  on the server.

rename OLD-NAME NEW-NAME
     Rename file OLD-NAME to NEW-NAME on the server.

site ARGS...
     Send a host-specific command to the server.  You will probably
     only need this if instructed by the server to use it.

quote ARGS...
     Send the raw FTP command sequence to the server.  You should be
     familiar with the FTP command set as defined in RFC959 before doing
     this.  Useful commands may include STAT and HELP.  Note also the
     mechanism for returning messages as described for the variable
     ZFTP_VERBOSE below, in particular that all messages from the
     control connection are sent to standard error.

close
quit
     Close the current data connection.  This unsets the shell
     parameters ZFTP_HOST, ZFTP_PORT, ZFTP_IP, ZFTP_SYSTEM, ZFTP_USER,
     ZFTP_ACCOUNT, ZFTP_PWD, ZFTP_TYPE and ZFTP_MODE.

session [ SESSNAME ]
     Allows multiple FTP sessions to be used at once.  The name of the
     session is an arbitrary string of characters; the default session
     is called `default'.  If this command is called without an
     argument, it will list all the current sessions; with an argument,
     it will either switch to the existing session called SESSNAME, or
     create a new session of that name.

     Each session remembers the status of the connection, the set of
     connection-specific shell parameters (the same set as are unset
     when a connection closes, as given in the description of close),
     and any user parameters specified with the params subcommand.
     Changing to a previous session restores those values; changing to
     a new session initialises them in the same way as if zftp had just
     been loaded.  The name of the current session is given by the
     parameter ZFTP_SESSION.

rmsession [ SESSNAME ]
     Delete a session; if a name is not given, the current session is
     deleted.  If the current session is deleted, the earliest existing
     session becomes the new current session, otherwise the current
     session is not changed.  If the session being deleted is the only
     one, a new session called `default' is created and becomes the
     current session; note that this is a new session even if the
     session being deleted is also called `default'. It is recommended
     that sessions not be deleted while background commands which use
     zftp are still active.



22.27.2 Parameters
------------------

The following shell parameters are used by zftp.  Currently none of
them are special.


ZFTP_TMOUT
     Integer.  The time in seconds to wait for a network operation to
     complete before returning an error.  If this is not set when the
     module is loaded, it will be given the default value 60.  A value
     of zero turns off timeouts.  If a timeout occurs on the control
     connection it will be closed.  Use a larger value if this occurs
     too frequently.

ZFTP_IP
     Readonly.  The IP address of the current connection in dot
     notation.

ZFTP_HOST
     Readonly.  The hostname of the current remote server.  If the host
     was opened as an IP number, ZFTP_HOST contains that instead; this
     saves the overhead for a name lookup, as IP numbers are most
     commonly used when a nameserver is unavailable.

ZFTP_PORT
     Readonly.  The number of the remote TCP port to which the
     connection is open (even if the port was originally specified as a
     named service).  Usually this is the standard FTP port, 21.

     In the unlikely event that your system does not have the
     appropriate conversion functions, this appears in network byte
     order.  If your system is little-endian, the port then consists of
     two swapped bytes and the standard port will be reported as 5376.
     In that case, numeric ports passed to zftp open will also need to
     be in this format.

ZFTP_SYSTEM
     Readonly.  The system type string returned by the server in
     response to an FTP SYST request.  The most interesting case is a
     string beginning "UNIX Type: L8", which ensures maximum
     compatibility with a local UNIX host.

ZFTP_TYPE
     Readonly.  The type to be used for data transfers , either `A' or
     `I'.   Use the type subcommand to change this.

ZFTP_USER
     Readonly.  The username currently logged in, if any.

ZFTP_ACCOUNT
     Readonly.  The account name of the current user, if any.  Most
     servers do not require an account name.

ZFTP_PWD
     Readonly.  The current directory on the server.

ZFTP_CODE
     Readonly.  The three digit code of the last FTP reply from the
     server as a string.  This can still be read after the connection
     is closed, and is not changed when the current session changes.

ZFTP_REPLY
     Readonly.  The last line of the last reply sent by the server.
     This can still be read after the connection is closed, and is not
     changed when the current session changes.

ZFTP_SESSION
     Readonly.  The name of the current FTP session; see the
     description of the session subcommand.

ZFTP_PREFS
     A string of preferences for altering aspects of zftp's behaviour.
     Each preference is a single character.  The following are defined:


    P
          Passive:  attempt to make the remote server initiate data
          transfers.  This is slightly more efficient than sendport
          mode.  If the letter S occurs later in the string, zftp will
          use sendport mode if passive mode is not available.

    S
          Sendport:  initiate transfers by the FTP PORT command.  If
          this occurs before any P in the string, passive mode will
          never be attempted.

    D
          Dumb:  use only the bare minimum of FTP commands.  This
          prevents the variables ZFTP_SYSTEM and ZFTP_PWD from being
          set, and will mean all connections default to ASCII type.  It
          may prevent ZFTP_SIZE from being set during a transfer if the
          server does not send it anyway (many servers do).


     If ZFTP_PREFS is not set when zftp is loaded, it will be set to a
     default of `PS', i.e. use passive mode if available, otherwise
     fall back to sendport mode.

ZFTP_VERBOSE
     A string of digits between 0 and 5 inclusive, specifying which
     responses from the server should be printed.  All responses go to
     standard error.  If any of the numbers 1 to 5 appear in the string,
     raw responses from the server with reply codes beginning with that
     digit will be printed to standard error.  The first digit of the
     three digit reply code is defined by RFC959 to correspond to:


    1.
          A positive preliminary reply.

    2.
          A positive completion reply.

    3.
          A positive intermediate reply.

    4.
          A transient negative completion reply.

    5.
          A permanent negative completion reply.


     It should be noted that, for unknown reasons, the reply `Service
     not available', which forces termination of a connection, is
     classified as 421, i.e. `transient negative', an interesting
     interpretation of the word `transient'.

     The code 0 is special:  it indicates that all but the last line of
     multiline replies read from the server will be printed to standard
     error in a processed format.  By convention, servers use this
     mechanism for sending information for the user to read.  The
     appropriate reply code, if it matches the same response, takes
     priority.

     If ZFTP_VERBOSE is not set when zftp is loaded, it will be set to
     the default value 450, i.e., messages destined for the user and
     all errors will be printed.  A null string is valid and specifies
     that no messages should be printed.



22.27.3 Functions
-----------------




zftp_chpwd
     If this function is set by the user, it is called every time the
     directory changes on the server, including when a user is logged
     in, or when a connection is closed.  In the last case, $ZFTP_PWD
     will be unset; otherwise it will reflect the new directory.

zftp_progress
     If this function is set by the user, it will be called during a
     get, put or append operation each time sufficient data has been
     received from the host.  During a get, the data is sent to
     standard output, so it is vital that this function should write to
     standard error or directly to the terminal, _not_ to standard
     output.

     When it is called with a transfer in progress, the following
     additional shell parameters are set:


    ZFTP_FILE
          The name of the remote file being transferred from or to.

    ZFTP_TRANSFER
          A G for a get operation and a P for a put operation.

    ZFTP_SIZE
          The total size of the complete file being transferred: the
          same as the first value provided by the remote and local
          subcommands for a particular file.  If the server cannot
          supply this value for a remote file being retrieved, it will
          not be set.  If input is from a pipe the value may be
          incorrect and correspond simply to a full pipe buffer.

    ZFTP_COUNT
          The amount of data so far transferred; a number between zero
          and $ZFTP_SIZE, if that is set.  This number is always
          available.


     The function is initially called with ZFTP_TRANSFER set
     appropriately and ZFTP_COUNT set to zero.  After the transfer is
     finished, the function will be called one more time with
     ZFTP_TRANSFER set to GF or PF, in case it wishes to tidy up.  It
     is otherwise never called twice with the same value of ZFTP_COUNT.

     Sometimes the progress meter may cause disruption.  It is up to the
     user to decide whether the function should be defined and to use
     unfunction when necessary.



22.27.4 Problems
----------------



A connection may not be opened in the left hand side of a pipe as this
occurs in a subshell and the file information is not updated in the main
shell.  In the case of type or mode changes or closing the connection
in a subshell, the information is returned but variables are not
updated until the next call to zftp.  Other status changes in subshells
will not be reflected by changes to the variables (but should be
otherwise harmless).

Deleting sessions while a zftp command is active in the background can
have unexpected effects, even if it does not use the session being
deleted.  This is because all shell subprocesses share information on
the state of all connections, and deleting a session changes the
ordering of that information.

On some operating systems, the control connection is not valid after a
fork(), so that operations in subshells, on the left hand side of a
pipeline, or in the background are not possible, as they should be.
This is presumably a bug in the operating system.

File: zsh.info,  Node: The zsh/zle Module,  Next: The zsh/zleparameter Module,  Prev: The zsh/zftp Module,  Up: Zsh Modules

22.28 The zsh/zle Module
========================



   The zsh/zle module contains the Zsh Line Editor.  See *note Zsh Line
Editor::.

File: zsh.info,  Node: The zsh/zleparameter Module,  Next: The zsh/zprof Module,  Prev: The zsh/zle Module,  Up: Zsh Modules

22.29 The zsh/zleparameter Module
=================================



   The zsh/zleparameter module defines two special parameters that can
be used to access internal information of the Zsh Line Editor (see
*note Zsh Line Editor::).


keymaps
     This array contains the names of the keymaps currently defined.

widgets
     This associative array contains one entry per widget defined. The
     name of the widget is the key and the value gives information
     about the widget. It is either the string `builtin' for builtin
     widgets, a string of the form `user:NAME' for user-defined widgets,
     where NAME is the name of the shell function implementing the
     widget, or it is a string of the form `completion:TYPE:NAME', for
     completion widgets. In the last case TYPE is the name of the
     builtin widgets the completion widget imitates in its behavior and
     NAME is the name of the shell function implementing the completion
     widget.


File: zsh.info,  Node: The zsh/zprof Module,  Next: The zsh/zpty Module,  Prev: The zsh/zleparameter Module,  Up: Zsh Modules

22.30 The zsh/zprof Module
==========================



   When loaded, the zsh/zprof causes shell functions to be profiled.
The profiling results can be obtained with the zprof builtin command
made available by this module.  There is no way to turn profiling off
other than unloading the module.


zprof [ -c ]
     Without the -c option, zprof lists profiling results to standard
     output.  The format is comparable to that of commands like gprof.

     At the top there is a summary listing all functions that were
     called at least once.  This summary is sorted in decreasing order
     of the amount of time spent in each.  The lines contain the number
     of the function in order, which is used in other parts of the list
     in suffixes of the form `[NUM]', then the number of calls made to
     the function.  The next three columns list the time in
     milliseconds spent in the function and its descendants, the average
     time in milliseconds spent in the function and its descendants per
     call and the percentage of time spent in all shell functions used
     in this function and its descendants.  The following three columns
     give the same information, but counting only the time spent in the
     function itself.  The final column shows the name of the function.

     After the summary, detailed information about every function that
     was invoked is listed, sorted in decreasing order of the amount of
     time spent in each function and its descendants.  Each of these
     entries consists of descriptions for the functions that called the
     function described, the function itself, and the functions that
     were called from it.  The description for the function itself has
     the same format as in the summary (and shows the same
     information).  The other lines don't show the number of the
     function at the beginning and have their function named indented to
     make it easier to distinguish the line showing the function
     described in the section from the surrounding lines.

     The information shown in this case is almost the same as in the
     summary, but only refers to the call hierarchy being displayed.
     For example, for a calling function the column showing the total
     running time lists the time spent in the described function and
     its descendants only for the times when it was called from that
     particular calling function.  Likewise, for a called function,
     this columns lists the total time spent in the called function and
     its descendants only for the times when it was called from the
     function described.

     Also in this case, the column showing the number of calls to a
     function also shows a slash and then the total number of
     invocations made to the called function.

     As long as the zsh/zprof module is loaded, profiling will be done
     and multiple invocations of the zprof builtin command will show the
     times and numbers of calls since the module was loaded.  With the
     -c option, the zprof builtin command will reset its internal
     counters and will not show the listing.


File: zsh.info,  Node: The zsh/zpty Module,  Next: The zsh/zselect Module,  Prev: The zsh/zprof Module,  Up: Zsh Modules

22.31 The zsh/zpty Module
=========================



   The zsh/zpty module offers one builtin:


zpty [ -e ] [ -b ] NAME [ ARG ... ]
     The arguments following NAME are concatenated with spaces between,
     then executed as a command, as if passed to the eval builtin.  The
     command runs under a newly assigned pseudo-terminal; this is
     useful for running commands non-interactively which expect an
     interactive environment.  The NAME is not part of the command, but
     is used to refer to this command in later calls to zpty.

     With the -e option, the pseudo-terminal is set up so that input
     characters are echoed.

     With the -b option, input to and output from the pseudo-terminal
     are made non-blocking.

zpty -d [ NAMES ... ]
     The second form, with the -d option, is used to delete commands
     previously started, by supplying a list of their NAMEs.  If no
     NAMES are given, all commands are deleted.  Deleting a command
     causes the HUP signal to be sent to the corresponding process.

zpty -w [ -n ] NAME [ STRINGS ... ]
     The -w option can be used to send the to command NAME the given
     STRINGS as input (separated by spaces).  If the -n option is _not_
     given, a newline is added at the end.

     If no STRINGS are provided, the standard input is copied to the
     pseudo-terminal; this may stop before copying the full input if the
     pseudo-terminal is non-blocking.

     Note that the command under the pseudo-terminal sees this input as
     if it were typed, so beware when sending special tty driver
     characters such as word-erase, line-kill, and end-of-file.

zpty -r [ -mt ] NAME [ PARAM [ PATTERN ] ]
     The -r option can be used to read the output of the command NAME.
     With only a NAME argument, the output read is copied to the
     standard output.  Unless the pseudo-terminal is non-blocking,
     copying continues until the command under the pseudo-terminal
     exits; when non-blocking, only as much output as is immediately
     available is copied.  The return status is zero if any output is
     copied.

     When also given a PARAM argument, at most one line is read and
     stored in the parameter named PARAM.  Less than a full line may be
     read if the pseudo-terminal is non-blocking.  The return status is
     zero if at least one character is stored in PARAM.

     If a PATTERN is given as well, output is read until the whole
     string read matches the PATTERN, even in the non-blocking case.
     The return status is zero if the string read matches the pattern,
     or if the command has exited but at least one character could
     still be read.  If the option -m is present, the return status is
     zero only if the pattern matches.  As of this writing, a maximum
     of one megabyte of output can be consumed this way; if a full
     megabyte is read without matching the pattern, the return status
     is non-zero.

     In all cases, the return status is non-zero if nothing could be
     read, and is 2 if this is because the command has finished.

     If the -r option is combined with the -t option, zpty tests
     whether output is available before trying to read.  If no output is
     available, zpty immediately returns the status 1.  When used with
     a PATTERN, the behaviour on a failed poll is similar to when the
     command has exited:  the return value is zero if at least one
     character could still be read even if the pattern failed to match.

zpty -t NAME
     The -t option without the -r option can be used to test whether
     the command NAME is still running.  It returns a zero status if
     the command is running and a non-zero value otherwise.

zpty [ -L ]
     The last form, without any arguments, is used to list the commands
     currently defined.  If the -L option is given, this is done in the
     form of calls to the zpty builtin.


File: zsh.info,  Node: The zsh/zselect Module,  Next: The zsh/zutil Module,  Prev: The zsh/zpty Module,  Up: Zsh Modules

22.32 The zsh/zselect Module
============================



   The zsh/zselect module makes available one builtin command:


zselect [ -rwe -t TIMEOUT -a ARRAY ] [ FD ... ]
     The zselect builtin is a front-end to the `select' system call,
     which blocks until a file descriptor is ready for reading or
     writing, or has an error condition, with an optional timeout.  If
     this is not available on your system, the command prints an error
     message and returns status 2 (normal errors return status 1).  For
     more information, see your systems documentation for man page
     select(3).  Note there is no connection with the shell builtin of
     the same name.

     Arguments and options may be intermingled in any order.  Non-option
     arguments are file descriptors, which must be decimal integers.  By
     default, file descriptors are to be tested for reading, i.e.
     zselect will return when data is available to be read from the
     file descriptor, or more precisely, when a read operation from the
     file descriptor will not block.  After a -r, -w and -e, the given
     file descriptors are to be tested for reading, writing, or error
     conditions.  These options and an arbitrary list of file
     descriptors may be given in any order.

     (The presence of an `error condition' is not well defined in the
     documentation for many implementations of the select system call.
     According to recent versions of the POSIX specification, it is
     really an _exception_ condition, of which the only standard
     example is out-of-band data received on a socket.  So zsh users
     are unlikely to find the -e option useful.)

     The option `-t TIMEOUT' specifies a timeout in hundredths of a
     second.  This may be zero, in which case the file descriptors will
     simply be polled and zselect will return immediately.  It is
     possible to call zselect with no file descriptors and a non-zero
     timeout for use as a finer-grained replacement for `sleep'; note,
     however, the return status is always 1 for a timeout.

     The option `-a ARRAY' indicates that array should be set to
     indicate the file descriptor(s) which are ready.  If the option is
     not given, the array reply will be used for this purpose.  The
     array will contain a string similar to the arguments for zselect.
     For example,


          zselect -t 0 -r 0 -w 1

     might return immediately with status 0 and $reply containing `-r 0
     -w 1' to show that both file descriptors are ready for the
     requested operations.

     The option `-A ASSOC' indicates that the associative array assoc
     should be set to indicate the file descriptor(s( which are ready.
     This option overrides the option -a, nor will reply be modified.
     The keys of assoc are the file descriptors, and the corresponding
     values are any of the characters `rwe' to indicate the condition.

     The command returns status 0 if some file descriptors are ready for
     reading.  If the operation timed out, or a timeout of 0 was given
     and no file descriptors were ready, or there was an error, it
     returns status 1 and the array will not be set (nor modified in
     any way).  If there was an error in the select operation the
     appropriate error message is printed.


File: zsh.info,  Node: The zsh/zutil Module,  Prev: The zsh/zselect Module,  Up: Zsh Modules

22.33 The zsh/zutil Module
==========================



   The zsh/zutil module only adds some builtins:


zstyle [ -L [ PATTERN [ STYLE ] ] ]
zstyle [ -e | - | -- ] PATTERN STYLE STRINGS ...
zstyle -d [ PATTERN [ STYLES ... ] ]
zstyle -g NAME [ PATTERN [ STYLE ] ]
zstyle -abs CONTEXT STYLE NAME [ SEP ]
zstyle -Tt CONTEXT STYLE [ STRINGS ...]
zstyle -m CONTEXT STYLE PATTERN
     This builtin command is used to define and lookup styles.  Styles
     are pairs of names and values, where the values consist of any
     number of strings.  They are stored together with patterns and
     lookup is done by giving a string, called the `context', which is
     compared to the patterns.  The definition stored for the first
     matching pattern will be returned.

     For ordering of comparisons, patterns are searched from most
     specific to least specific, and patterns that are equally specific
     keep the order in which they were defined.  A pattern is
     considered to be more specific than another if it contains more
     components (substrings separated by colons) or if the patterns for
     the components are more specific, where simple strings are
     considered to be more specific than patterns and complex patterns
     are considered to be more specific than the pattern `*'.

     The first form (without arguments) lists the definitions.  Styles
     are shown in alphabetic order and patterns are shown in the order
     zstyle will test them.

     If the -L option is given, listing is done in the form of calls to
     zstyle.  The optional first argument is a pattern which will be
     matched against the string supplied as the pattern for the
     context; note that this means, for example, `zstyle -L
     ":completion:*"' will match any supplied pattern beginning
     `:completion:', not just ":completion:*":  use ":completion:\*" to
     match that.  The optional second argument limits the output to a
     specific style (not a pattern).  -L is not compatible with any
     other options.

     The other forms are the following:


    zstyle [ - | -- | -e ] PATTERN STYLE STRINGS ...
          Defines the given STYLE for the PATTERN with the STRINGS as
          the value.  If the -e option is given, the STRINGS will be
          concatenated (separated by spaces) and the resulting string
          will be evaluated (in the same way as it is done by the eval
          builtin command) when the style is looked up.  In this case
          the parameter `reply' must be assigned to set the strings
          returned after the evaluation.  Before evaluating the value,
          reply is unset, and if it is still unset after the
          evaluation, the style is treated as if it were not set.

    zstyle -d [ PATTERN [ STYLES ... ] ]
          Delete style definitions. Without arguments all definitions
          are deleted, with a PATTERN all definitions for that pattern
          are deleted and if any STYLES are given, then only those
          styles are deleted for the PATTERN.

    zstyle -g NAME [ PATTERN [ STYLE ] ]
          Retrieve a style definition. The NAME is used as the name of
          an array in which the results are stored. Without any further
          arguments, all PATTERNS defined are returned. With a PATTERN
          the styles defined for that pattern are returned and with
          both a PATTERN and a STYLE, the value strings of that
          combination is returned.


     The other forms can be used to look up or test patterns.


    zstyle -s CONTEXT STYLE NAME [ SEP ]
          The parameter NAME is set to the value of the style
          interpreted as a string.  If the value contains several
          strings they are concatenated with spaces (or with the SEP
          string if that is given) between them.

    zstyle -b CONTEXT STYLE NAME
          The value is stored in NAME as a boolean, i.e. as the string
          `yes' if the value has only one string and that string is
          equal to one of `yes', `true', `on', or `1'. If the value is
          any other string or has more than one string, the parameter
          is set to `no'.

    zstyle -a CONTEXT STYLE NAME
          The value is stored in NAME as an array. If NAME is declared
          as an associative array,  the first, third, etc. strings are
          used as the keys and the other strings are used as the values.

    zstyle -t CONTEXT STYLE [ STRINGS ...]
    zstyle -T CONTEXT STYLE [ STRINGS ...]
          Test the value of a style, i.e. the -t option only returns a
          status (sets $?).  Without any STRINGS the return status is
          zero if the style is defined for at least one matching
          pattern, has only one string in its value, and that is equal
          to one of `true', `yes', `on' or `1'. If any STRINGS are
          given the status is zero if and only if at least one of the
          STRINGS is equal to at least one of the strings in the value.
          If the style is not defined, the status is 2.

          The -T option tests the values of the style like -t, but it
          returns status zero (rather than 2) if the style is not
          defined for any matching pattern.

    zstyle -m CONTEXT STYLE PATTERN
          Match a value. Returns status zero if the PATTERN matches at
          least one of the strings in the value.


zformat -f PARAM FORMAT SPECS ...
zformat -a ARRAY SEP SPECS ...
     This builtin provides two different forms of formatting. The first
     form is selected with the -f option. In this case the FORMAT
     string will be modified by replacing sequences starting with a
     percent sign in it with strings from the SPECS.  Each SPEC should
     be of the form `CHAR:STRING' which will cause every appearance of
     the sequence `%CHAR' in FORMAT to be replaced by the STRING.  The
     `%' sequence may also contain optional minimum and maximum field
     width specifications between the `%' and the `CHAR' in the form
     `%MIN.MAXc', i.e. the minimum field width is given first and if
     the maximum field width is used, it has to be preceded by a dot.
     Specifying a minimum field width makes the result be padded with
     spaces to the right if the STRING is shorter than the requested
     width.  Padding to the left can be achieved by giving a negative
     minimum field width.  If a maximum field width is specified, the
     STRING will be truncated after that many characters.  After all
     `%' sequences for the given SPECS have been processed, the
     resulting string is stored in the parameter PARAM.

     The %-escapes also understand ternary expressions in the form used
     by prompts.  The % is followed by a `(' and then an ordinary
     format specifier character as described above.  There may be a set
     of digits either before or after the `('; these specify a test
     number, which defaults to zero.  Negative numbers are also
     allowed.  An arbitrary delimiter character follows the format
     specifier, which is followed by a piece of `true' text, the
     delimiter character again, a piece of `false' text, and a closing
     parenthesis.  The complete expression (without the digits) thus
     looks like `%(X.TEXT1.TEXT2)', except that the `.' character is
     arbitrary.  The value given for the format specifier in the
     CHAR:STRING expressions is evaluated as a mathematical expression,
     and compared with the test number.  If they are the same, TEXT1 is
     output, else TEXT2 is output.  A parenthesis may be escaped in
     TEXT2 as %).  Either of TEXT1 or TEXT2 may contain nested
     %-escapes.

     For example:


          zformat -f REPLY "The answer is '%3(c.yes.no)'." c:3

     outputs "The answer is 'yes'." to REPLY since the value for the
     format specifier c is 3, agreeing with the digit argument to the
     ternary expression.

     The second form, using the -a option, can be used for aligning
     strings.  Here, the SPECS are of the form `LEFT:RIGHT' where
     `LEFT' and `RIGHT' are arbitrary strings.  These strings are
     modified by replacing the colons by the SEP string and padding the
     LEFT strings with spaces to the right so that the SEP strings in
     the result (and hence the RIGHT strings after them) are all
     aligned if the strings are printed below each other.  All strings
     without a colon are left unchanged and all strings with an empty
     RIGHT string have the trailing colon removed.  In both cases the
     lengths of the strings are not used to determine how the other
     strings are to be aligned.  The resulting strings are stored in
     the ARRAY.

zregexparse
     This implements some internals of the _regex_arguments function.

zparseopts [ -D ] [ -K ] [ -E ] [ -a ARRAY ] [ -A ASSOC ] SPECS
     This builtin simplifies the parsing of options in positional
     parameters, i.e. the set of arguments given by $*.  Each SPEC
     describes one option and must be of the form `OPT[=ARRAY]'.  If an
     option described by OPT is found in the positional parameters it
     is copied into the ARRAY specified with the -a option; if the
     optional `=ARRAY' is given, it is instead copied into that array.

     Note that it is an error to give any SPEC without an `=ARRAY'
     unless one of the -a or -A options is used.

     Unless the -E option is given, parsing stops at the first string
     that isn't described by one of the SPECS.  Even with -E, parsing
     always stops at a positional parameter equal to `-' or `--'.

     The OPT description must be one of the following.  Any of the
     special characters can appear in the option name provided it is
     preceded by a backslash.


    NAME
    NAME+
          The NAME is the name of the option without the leading `-'.
          To specify a GNU-style long option, one of the usual two
          leading `-' must be included in NAME; for example, a `--file'
          option is represented by a NAME of `-file'.

          If a `+' appears after NAME, the option is appended to ARRAY
          each time it is found in the positional parameters; without
          the `+' only the _last_ occurrence of the option is preserved.

          If one of these forms is used, the option takes no argument,
          so parsing stops if the next positional parameter does not
          also begin with `-' (unless the -E option is used).

    NAME:
    NAME:-
    NAME::
          If one or two colons are given, the option takes an argument;
          with one colon, the argument is mandatory and with two colons
          it is optional.  The argument is appended to the ARRAY after
          the option itself.

          An optional argument is put into the same array element as
          the option name (note that this makes empty strings as
          arguments indistinguishable).  A mandatory argument is added
          as a separate element unless the `:-' form is used, in which
          case the argument is put into the same element.

          A `+' as described above may appear between the NAME and the
          first colon.


     The options of zparseopts itself are:


    -a ARRAY
          As described above, this names the default array in which to
          store the recognised options.

    -A ASSOC
          If this is given, the options and their values are also put
          into an associative array with the option names as keys and
          the arguments (if any) as the values.

    -D
          If this option is given, all options found are removed from
          the positional parameters of the calling shell or shell
          function, up to but not including any not described by the
          SPECS.  This is similar to using the shift builtin.

    -K
          With this option, the arrays specified with the -a and -A
          options and with the `=ARRAY' forms are kept unchanged when
          none of the SPECS for them is used.  This allows assignment
          of default values to them before calling zparseopts.

    -E
          This changes the parsing rules to _not_ stop at the first
          string that isn't described by one of the SPECs.  It can be
          used to test for or (if used together with -D) extract
          options and their arguments, ignoring all other options and
          arguments that may be in the positional parameters.


     For example,


          set -- -a -bx -c y -cz baz -cend
          zparseopts a=foo b:=bar c+:=bar

     will have the effect of


          foo=(-a)
          bar=(-b x -c y -c z)

     The arguments from `baz' on will not be used.

     As an example for the -E option, consider:


          set -- -a x -b y -c z arg1 arg2
          zparseopts -E -D b:=bar

     will have the effect of


          bar=(-b y)
          set -- -a x -c z arg1 arg2

     I.e., the option -b and its arguments are taken from the
     positional parameters and put into the array bar.


File: zsh.info,  Node: Calendar Function System,  Next: TCP Function System,  Prev: Zsh Modules,  Up: Top

23 Calendar Function System
***************************



23.1 Description
================

The shell is supplied with a series of functions to replace and enhance
the traditional Unix calendar programme, which warns the user of
imminent or future events, details of which are stored in a text file
(typically calendar in the user's home directory).  The version
provided here includes a mechanism for alerting the user when an event
is due.

In addition a function age is provided that can be used in a glob
qualifier; it allows files to be selected based on their modification
times.

The format of the calendar file and the dates used there in and in the
age function are described first, then the functions that can be called
to examine and modify the calendar file.

The functions here depend on the availability of the zsh/datetime
module which is usually installed with the shell.  The library function
strptime() must be available; it is present on most recent operating
systems.



* Menu:

* Calendar File and Date Formats::
* Calendar System User Functions::
* Calendar Styles::
* Calendar Utility Functions::
* Calendar Bugs::


File: zsh.info,  Node: Calendar File and Date Formats,  Next: Calendar System User Functions,  Up: Calendar Function System

23.2 File and Date Formats
==========================



23.2.1 Calendar File Format
---------------------------

The calendar file is by default ~/calendar.  This can be configured by
the calendar-file style, see *note Calendar Styles::.  The basic format
consists of a series of separate lines, with no indentation, each
including a date and time specification followed by a description of
the event.

Various enhancements to this format are supported, based on the syntax
of Emacs calendar mode.  An indented line indicates a continuation line
that continues the description of the event from the preceding line
(note the date may not be continued in this way).  An initial ampersand
(&) is ignored for compatibility.

An indented line on which the first non-whitespace character is # is
not displayed with the calendar entry, but is still scanned for
information.  This can be used to hide information useful to the
calendar system but not to the user, such as the unique identifier used
by calendar_add.

The Emacs extension that a date with no description may refer to a
number of succeeding events at different times is not supported.

Unless the done-file style has been altered, any events which have been
processed are appended to the file with the same name as the calendar
file with the suffix .done, hence ~/calendar.done by default.

An example is shown below.



23.2.2 Date Format
------------------

The format of the date and time is designed to allow flexibility without
admitting ambiguity.  (The words `date' and `time' are both used in the
documentation below; except where specifically noted this implies a
string that may include both a date and a time specification.)  Note
that there is no localization support; month and day names must be in
English and separator characters are fixed.  Matching is case
insensitive, and only the first three letters of the names are
significant, although as a special case a form beginning "month" does
not match "Monday".  Furthermore, time zones are not handled; all times
are assumed to be local.

It is recommended that, rather than exploring the intricacies of the
system, users find a date format that is natural to them and stick to
it.  This will avoid unexpected effects.  Various key facts should be
noted.


   * In particular, note the confusion between MONTH/DAY/YEAR and
     DAY/MONTH/YEAR when the month is numeric; these formats should be
     avoided if at all possible.  Many alternatives are available.

   * The year must be given in full to avoid confusion, and only years
     from 1900 to 2099 inclusive are matched.

The following give some obvious examples; users finding here a format
they like and not subject to vagaries of style may skip the full
description.  As dates and times are matched separately (even though
the time may be embedded in the date), any date format may be mixed
with any format for the time of day provide the separators are clear
(whitespace, colons, commas).


     2007/04/03 13:13
     2007/04/03:13:13
     2007/04/03 1:13 pm
     3rd April 2007, 13:13
     April 3rd 2007 1:13 p.m.
     Apr 3, 2007 13:13
     Tue Apr 03 13:13:00 2007
     13:13 2007/apr/3

More detailed rules follow.

Times are parsed and extracted before dates.  They must use colons to
separate hours and minutes, though a dot is allowed before seconds if
they are present.  This limits time formats to the following:


   * HH:MM[:SS[.FFFFF]] [am|pm|a.m.|p.m.]

   * HH:MM.SS[.FFFFF] [am|pm|a.m.|p.m.]

Here, square brackets indicate optional elements, possibly with
alternatives.  Fractions of a second are recognised but ignored.  For
absolute times (the normal format require by the calendar file and the
age function) a date is mandatory but a time of day is not; the time
returned is at the start of the date.  One variation is allowed: if
a.m. or p.m. or one of their variants is present, an hour without a
minute is allowed, e.g. 3 p.m..

Time zones are not handled, though if one is matched following a time
specification it will be removed to allow a surrounding date to be
parsed.  This only happens if the format of the timezone is not too
unusual.  The following are examples of forms that are understood:


     +0100
     GMT
     GMT-7
     CET+1CDT

Any part of the timezone that is not numeric must have exactly three
capital letters in the name.

Dates suffer from the ambiguity between DD/MM/YYYY and MM/DD/YYYY.  It
is recommended this form is avoided with purely numeric dates, but use
of ordinals, eg. 3rd/04/2007, will resolve the ambiguity as the ordinal
is always parsed as the day of the month.  Years must be four digits
(and the first two must be 19 or 20); 03/04/08 is not recognised.  Other
numbers may have leading zeroes, but they are not required.  The
following are handled:


   * YYYY/MM/DD

   * YYYY-MM-DD

   * YYYY/MNM/DD

   * YYYY-MNM-DD

   * DD[th|st|rd] MNM[,] [ YYYY ]

   * MNM DD[th|st|rd][,] [ YYYY ]

   * DD[th|st|rd]/MM[,] YYYY

   * DD[th|st|rd]/MM/YYYY

   * MM/DD[th|st|rd][,] YYYY

   * MM/DD[th|st|rd]/YYYY

Here, MNM is at least the first three letters of a month name, matched
case-insensitively.  The remainder of the month name may appear but its
contents are irrelevant, so janissary, febrile, martial, apricot,
maybe, junta, etc. are happily handled.

Where the year is shown as optional, the current year is assumed.  There
are only two such cases, the form Jun 20 or 14 September (the only two
commonly occurring forms, apart from a "the" in some forms of English,
which isn't currently supported).  Such dates will of course become
ambiguous in the future, so should ideally be avoided.

Times may follow dates with a colon, e.g. 1965/07/12:09:45; this is in
order to provide a format with no whitespace.  A comma and whitespace
are allowed, e.g. 1965/07/12, 09:45.  Currently the order of these
separators is not checked, so illogical formats such as 1965/07/12, :
,09:45 will also be matched.  For simplicity such variations are not
shown in the list above.  Otherwise, a time is only recognised as being
associated with a date if there is only whitespace in between, or if the
time was embedded in the date.

Days of the week are not normally scanned, but will be ignored if they
occur at the start of the date pattern only.  However, in contexts
where it is useful to specify dates relative to today, days of the week
with no other date specification may be given.  The day is assumed to
be either today or within the past week.  Likewise, the words yesterday,
today and tomorrow are handled.  All matches are case-insensitive.
Hence if today is Monday, then Sunday is equivalent to yesterday,
Monday is equivalent to today, but Tuesday gives a date six days ago.
This is not generally useful within the calendar file.  Dates in this
format may be combined with a time specification; for example Tomorrow,
8 p.m..

For example, the standard date format:


     Fri Aug 18 17:00:48 BST 2006

is handled by matching HH:MM:SS and removing it together with the
matched (but unused) time zone.  This leaves the following:


     Fri Aug 18 2006

Fri is ignored and the rest is matched according to the standard rules.



23.2.3 Relative Time Format
---------------------------

In certain places relative times are handled.  Here, a date is not
allowed; instead a combination of various supported periods are
allowed, together with an optional time.  The periods must be in order
from most to least significant.

In some cases, a more accurate calculation is possible when there is an
anchor date:  offsets of months or years pick the correct day, rather
than being rounded, and it is possible to pick a particular day in a
month as `(1st Friday)', etc., as described in more detail below.

Anchors are available in the following cases.  If one or two times are
passed to the function calendar, the start time acts an anchor for the
end time when the end time is relative (even if the start time is
implicit).  When examining calendar files, the scheduled event being
examined anchors the warning time when it is given explicitly by means
of the WARN keyword; likewise, the scheduled event anchors a repetition
period when given by the RPT keyword, so that specifications such as
RPT 2 months, 3rd Thursday are handled properly.  Finally, the -R
argument to calendar_scandate directly provides an anchor for relative
calculations.

The periods handled, with possible abbreviations are:


Years
     years, yrs, ys, year, yr, y, yearly.  A year is 365.25 days unless
     there is an anchor.

Months
     months, mons, mnths, mths, month, mon, mnth, mth, monthly.  Note
     that m, ms, mn, mns are ambiguous and are _not_ handled.  A month
     is a period of 30 days rather than a calendar month unless there
     is an anchor.

Weeks
     weeks, wks, ws, week, wk, w, weekly

Days
     days, dys, ds, day, dy, d, daily

Hours
     hours, hrs, hs, hour, hr, h, hourly

Minutes
     minutes, mins, minute, min, but _not_ m, ms, mn or mns

Seconds
     seconds, secs, ss, second, sec, s


Spaces between the numbers are optional, but are required between items,
although a comma may be used (with or without spaces).

The forms yearly to hourly allow the number to be omitted; it is
assumed to be 1.  For example, 1 d and daily are equivalent.  Note that
using those forms with plurals is confusing; 2 yearly is the same as 2
years, _not_ twice yearly, so it is recommended they only be used
without numbers.

When an anchor time is present, there is an extension to handle regular
events in the form of the Nth SOMEday of the month.  Such a
specification must occur immediately after any year and month
specification, but before any time of day, and must be in the form
N(th|st|rd) DAY, for example 1st Tuesday or 3rd Monday.  As in other
places, days are matched case insensitively, must be in English, and
only the first three letters are significant except that a form
beginning `month' does not match `Monday'.  No attempt is made to
sanitize the resulting date; attempts to squeeze too many occurrences
into a month will push the day into the next month (but in the obvious
fashion, retaining the correct day of the week).

Here are some examples:


     30 years 3 months 4 days 3:42:41
     14 days 5 hours
     Monthly, 3rd Thursday
     4d,10hr


23.2.4 Example
--------------

Here is an example calendar file.  It uses a consistent date format, as
recommended above.


     Feb 1, 2006 14:30 Pointless bureaucratic meeting
     Mar 27, 2006 11:00 Mutual recrimination and finger pointing
       Bring water pistol and waterproofs
     Mar 31, 2006 14:00 Very serious managerial pontification
       # UID 12C7878A9A50
     Apr 10, 2006 13:30 Even more pointless blame assignment exercise WARN 30 mins
     May 18, 2006 16:00 Regular moaning session RPT monthly, 3rd Thursday

The second entry has a continuation line.  The third entry has a
continuation line that will not be shown when the entry is displayed,
but the unique identifier will be used by the calendar_add function when
updating the event.  The fourth entry will produce a warning 30 minutes
before the event (to allow you to equip yourself appropriately).  The
fifth entry repeats after a month on the 3rd Thursday, i.e. June 15,
2006, at the same time.



File: zsh.info,  Node: Calendar System User Functions,  Next: Calendar Styles,  Prev: Calendar File and Date Formats,  Up: Calendar Function System

23.3 User Functions
===================

This section describes functions that are designed to be called
directly by the user.  The first part describes those functions
associated with the user's calendar; the second part describes the use
in glob qualifiers.



23.3.1 Calendar system functions
--------------------------------


calendar [ -abdDsv ] [ -C CALFILE ] [ -n NUM ] [ -S SHOWPROG ] [ [ START ] END ](
calendar -r [ -abdDrsv ] [ -C CALFILE ] [ -n NUM ] [ -S SHOWPROG ] [ START ]
     Show events in the calendar.

     With no arguments, show events from the start of today until the
     end of the next working day after today.  In other words, if today
     is Friday, Saturday, or Sunday, show up to the end of the
     following Monday, otherwise show today and tomorrow.

     If END is given, show events from the start of today up to the time
     and date given, which is in the format described in the previous
     section.  Note that if this is a date the time is assumed to be
     midnight at the start of the date, so that effectively this shows
     all events before the given date.

     END may start with a +, in which case the remainder of the
     specification is a relative time format as described in the
     previous section indicating the range of time from the start time
     that is to be included.

     If START is also given, show events starting from that time and
     date.  The word now can be used to indicate the current time.

     To implement an alert when events are due, include calendar -s in
     your ~/.zshrc file.

     Options:


    -a
          Show all items in the calendar, regardless of the start and
          end.

    -b
          Brief:  don't display continuation lines (i.e. indented lines
          following the line with the date/time), just the first line.

    -B LINES
          Brief: display at most the first LINES lines of the calendar
          entry.  `-B 1' is equivalent to `-b'.

    -C CALFILE
          Explicitly specify a calendar file instead of the value of
          the calendar-file style or the the default ~/calendar.

    -d
          Move any events that have passed from the calendar file to the
          "done" file, as given by the done-file style or the default
          which is the calendar file with .done appended.  This option
          is implied by the -s option.

    -D
          Turns off the option -d, even if the -s option is also
          present.

    -n NUM, -NUM
          Show at least NUM events, if present in the calendar file,
          regardless of the start and end.

    -r
          Show all the remaining options in the calendar, ignoring the
          given end time.  The start time is respected; any argument
          given is treated as a start time.

    -s
          Use the shell's sched command to schedule a timed event that
          will warn the user when an event is due.  Note that the sched
          command only runs if the shell is at an interactive prompt; a
          foreground task blocks the scheduled task from running until
          it is finished.

          The timed event usually runs the programme calendar_show to
          show the event, as described in *note Calendar Utility
          Functions::.

          By default, a warning of the event is shown five minutes
          before it is due.  The warning period can be configured by
          the style warn-time or for a single calendar entry by
          including WARN RELTIME in the first line of the entry, where
          RELTIME is one of the usual relative time formats.

          A repeated event may be indicated by including RPT RELDATE in
          the first line of the entry.  After the scheduled event has
          been displayed it will be re-entered into the calendar file
          at a time RELDATE after the existing event.  Note that this
          is currently the only use made of the repeat count, so that
          it is not possible to query the schedule for a recurrence of
          an event in the calendar until the previous event has passed.

          If RPT is used, it is also possible to specify that certain
          recurrences of an event are rescheduled or cancelled.  This is
          done with the OCCURRENCE keyword, followed by whitespace and
          the date and time of the occurrence in the regular sequence,
          followed by whitespace and either the date and time of the
          rescheduled event or the exact string CANCELLED.  In this
          case the date and time must be in exactly the "date with
          local time" format used by the text/calendar MIME type (RFC
          2445), <YYYY><MM><DD>T<HH><MM><SS> (note the presence of the
          literal character T).  The first word (the regular
          recurrence) may be something other than a proper date/time to
          indicate that the event is additional to the normal sequence;
          a convention that retains the formatting appearance is
          XXXXXXXXTXXXXXX.

          Furthermore, it is useful to record the next regular
          recurrence (as then the displayed date may be for a
          rescheduled event so cannot be used for calculating the
          regular sequence).  This is specified by RECURRENCE and a
          time or date in the same format.  calendar_add adds such an
          indication when it encounters a recurring event that does not
          include one, based on the headline date/time.

          If calendar_add is used to update occurrences the UID keyword
          described there should be present in both the existing entry
          and the added occurrence in order to identify recurring event
          sequences.

          For example,


               Thu May 6, 2010 11:00 Informal chat RPT 1 week
                 # RECURRENCE 20100506T110000
                 # OCCURRENCE 20100513T110000 20100513T120000
                 # OCCURRENCE 20100520T110000 CANCELLED

          The event that occurs at 11:00 on 13th May 2010 is
          rescheduled an hour later.  The event that occurs a week
          later is cancelled.  The occurrences are given on a
          continuation line starting with a # character so will not
          usually be displayed as part of the event.  As elsewhere, no
          account of time zones is taken with the times. After the next
          event occurs the headline date/time will be `Thu May 13, 2010
          12:00' while the RECURRENCE date/time will be
          `20100513T110000' (note that cancelled and moved events are
          not taken account of in the RECURRENCE, which records what
          the next regular recurrence is, but they are accounted for in
          the headline date/time).

          It is safe to run calendar -s to reschedule an existing event
          (if the calendar file has changed, for example), and also to
          have it running in multiples instances of the shell since the
          calendar file is locked when in use.

          By default, expired events are moved to the "done" file; see
          the -d option.  Use -D to prevent this.

    -S SHOWPROG
          Explicitly specify a programme to be used for showing events
          instead of the value of the show-prog style or the default
          calendar_show.

    -v
          Verbose:  show more information about stages of processing.
          This is useful for confirming that the function has
          successfully parsed the dates in the calendar file.


calendar_add [ -BL ] EVENT ...
     Adds a single event to the calendar in the appropriate location.
     The event can contain multiple lines, as described in *note
     Calendar File and Date Formats::.  Using this function ensures
     that the calendar file is sorted in date and time order.  It also
     makes special arrangements for locking the file while it is
     altered.  The old calendar is left in a file with the suffix .old.

     The option -B indicates that backing up the calendar file will be
     handled by the caller and should not be performed by calendar_add.
     The option -L indicates that calendar_add does not need to lock the
     calendar file as it is already locked.  These options will not
     usually be needed by users.

     If the style reformat-date is true, the date and time of the new
     entry will be rewritten into the standard date format:  see the
     descriptions of this style and the style date-format.

     The function can use a unique identifier stored with each event to
     ensure that updates to existing events are treated correctly.  The
     entry should contain the word UID, followed by whitespace,
     followed by a word consisting entirely of hexadecimal digits of
     arbitrary length (all digits are significant, including leading
     zeroes).  As the UID is not directly useful to the user, it is
     convenient to hide it on an indented continuation line starting
     with a #, for example:


          Aug 31, 2007 09:30  Celebrate the end of the holidays
            # UID 045B78A0

     The second line will not be shown by the calendar function.

     It is possible to specify the RPT keyword followed by CANCELLED
     instead of a relative time.  This causes any matched event or
     series of events to be cancelled (the original event does not have
     to be marked as recurring in order to be cancelled by this
     method).  A UID is required in order to match an existing event in
     the calendar.

     calendar_add will attempt to manage recurrences and occurrences of
     repeating events as described for event scheduling by calendar -s
     above.  To reschedule or cancel a single event calendar_add should
     be called with an entry that includes the correct UID but does
     _not_ include the RPT keyword as this is taken to mean the entry
     applies to a series of repeating events and hence replaces all
     existing information.  Each rescheduled or cancelled occurrence
     must have an OCCURRENCE keyword in the entry passed to
     calendar_add which will be merged into the calendar file.  Any
     existing reference to the occurrence is replaced.  An occurrence
     that does not refer to a valid existing event is added as a
     one-off occurrence to the same calendar entry.

calendar_edit
     This calls the user's editor to edit the calendar file.  If there
     are arguments, they are taken as the editor to use (the file name
     is appended to the commands); otherwise, the editor is given by the
     variable VISUAL, if set, else the variable EDITOR.

     If the calendar scheduler was running, then after editing the file
     calendar -s is called to update it.

     This function locks out the calendar system during the edit.
     Hence it should be used to edit the calendar file if there is any
     possibility of a calendar event occurring meanwhile.  Note this
     can lead to another shell with calendar functions enabled hanging
     waiting for a lock, so it is necessary to quit the editor as soon
     as possible.

calendar_parse CALENDAR-ENTRY
     This is the internal function that analyses the parts of a calendar
     entry, which is passed as the only argument.  The function returns
     status 1 if the argument could not be parsed as a calendar entry
     and status 2 if the wrong number of arguments were passed; it also
     sets the parameter reply to an empty associative array.  Otherwise,
     it returns status 0 and sets elements of the associative array
     reply as follows:
    timeNL()The time as a string of digits in the same units as
          $EPOCHSECONDS

    schedtimeNL()The regularly scheduled time.  This may differ from
          the actual event time time if this is a recurring event and
          the next occurrence has been rescheduled.  Then time gives
          the actual time and schedtime the time of the regular
          recurrence before modification.

    text1
          The text from the line not including the date and time of the
          event, but including any WARN or RPT keywords and values.

    warntimeNL()Any warning time given by the WARN keyword as a string
          of digits containing the time at which to warn in the same
          units as $EPOCHSECONDS.  (Note this is an absolute time, not
          the relative time passed down.)  Not set no WARN keyword and
          value were matched.

    warnstrNL()The raw string matched after the WARN keyword, else unset.

    rpttimeNL()Any recurrence time given by the RPT keyword as a string
          of digits containing the time of the recurrence in the same
          units as $EPOCHSECONDS.  (Note this is an absolute time.)
          Not set if no RPT keyword and value were matched.

    schedrpttimeNL()The next regularly scheduled occurrence of a recurring
          event before modification.  This may differ from rpttime,
          which is the actual time of the event that may have been
          rescheduled from the regular time.

    rptstrNL()The raw string matched after the RPT keyword, else unset.

    text2
          The text from the line after removal of the date and any
          keywords and values.

     )

calendar_showdate [ -r ] [ -f FMT ] DATE-SPEC ...
     The given DATE-SPEC is interpreted and the corresponding date and
     time printed.  If the initial DATE-SPEC begins with a + or - it is
     treated as relative to the current time; DATE-SPECs after the
     first are treated as relative to the date calculated so far and a
     leading + is optional in that case.  This allows one to use the
     system as a date calculator.  For example, calendar_showdate '+1
     month, 1st Friday' shows the date of the first Friday of next
     month.

     With the option -r nothing is printed but the value of the date and
     time in seconds since the epoch is stored in the parameter REPLY.

     With the option -f FMT the given date/time conversion format is
     passed to strftime; see notes on the date-format style below.

     In order to avoid ambiguity with negative relative date
     specifications, options must occur in separate words; in other
     words, -r and -f should not be combined in the same word.

calendar_sort
     Sorts the calendar file into date and time order.    The old
     calendar is left in a file with the suffix .old.



23.3.2 Glob qualifiers
----------------------



The function age can be autoloaded and use separately from the calendar
system, although it uses the function calendar_scandate for date
formatting.  It requires the zsh/stat builtin, but uses only the
builtin zstat.

age selects files having a given modification time for use as a glob
qualifier.  The format of the date is the same as that understood by
the calendar system, described in *note Calendar File and Date
Formats::.

The function can take one or two arguments, which can be supplied either
directly as command or arguments, or separately as shell parameters.


     print *(e:age 2006/10/04 2006/10/09:)

The example above matches all files modified between the start of those
dates.  The second argument may alternatively be a relative time
introduced by a +:


     print *(e:age 2006/10/04 +5d:)

The example above is equivalent to the previous example.

In addition to the special use of days of the week, today and
yesterday, times with no date may be specified; these apply to today.
Obviously such uses become problematic around midnight.


     print *(e-age 12:00 13:30-)

The example above shows files modified between 12:00 and 13:00 today.


     print *(e:age 2006/10/04:)

The example above matches all files modified on that date.  If the
second argument is omitted it is taken to be exactly 24 hours after the
first argument (even if the first argument contains a time).


     print *(e-age 2006/10/04:10:15 2006/10/04:10:45-)

The example above supplies times.  Note that whitespace within the time
and date specification must be quoted to ensure age receives the correct
arguments, hence the use of the additional colon to separate the date
and time.


     AGEREF1=2006/10/04:10:15
     AGEREF2=2006/10/04:10:45
     print *(+age)

This shows the same example before using another form of argument
passing.  The dates and times in the parameters AGEREF1 and AGEREF2
stay in effect until unset, but will be overridden if any argument is
passed as an explicit argument to age.  Any explicit argument causes
both parameters to be ignored.



File: zsh.info,  Node: Calendar Styles,  Next: Calendar Utility Functions,  Prev: Calendar System User Functions,  Up: Calendar Function System

23.4 Styles
===========

The zsh style mechanism using the zstyle command is describe in *note
The zsh/zutil Module::.  This is the same mechanism used in the
completion system.

The styles below are all examined in the context :datetime:FUNCTION:,
for example :datetime:calendar:.


calendar-file
     The location of the main calendar.  The default is ~/calendar.

date-format
     A strftime format string (see man page strftime(3)) with the zsh
     extensions providing various numbers with no leading zero or space
     if the number is a single digit as described for the %D{STRING}
     prompt format in *note Prompt Expansion::.

     This is used for outputting dates in calendar, both to support the
     -v option and when adding recurring events back to the calendar
     file, and in calendar_showdate as the final output format.

     If the style is not set, the default used is similar the standard
     system format as output by the date command (also known as `ctime
     format'): `%a %b %d %H:%M:%S %Z %Y'.

done-file
     The location of the file to which events which have passed are
     appended.  The default is the calendar file location with the
     suffix .done.  The style may be set to an empty string in which
     case a "done" file will not be maintained.

reformat-date
     Boolean, used by calendar_add.  If it is true, the date and time
     of new entries added to the calendar will be reformatted to the
     format given by the style date-format or its default.  Only the
     date and time of the event itself is reformatted; any subsidiary
     dates and times such as those associated with repeat and warning
     times are left alone.

show-prog
     The programme run by calendar for showing events.  It will be
     passed the start time and stop time of the events requested in
     seconds since the epoch followed by the event text.  Note that
     calendar -s uses a start time and stop time equal to one another
     to indicate alerts for specific events.

     The default is the function calendar_show.

warn-time
     The time before an event at which a warning will be displayed, if
     the first line of the event does not include the text EVENT
     RELTIME.  The default is 5 minutes.



File: zsh.info,  Node: Calendar Utility Functions,  Next: Calendar Bugs,  Prev: Calendar Styles,  Up: Calendar Function System

23.5 Utility functions
======================


calendar_lockfiles
     Attempt to lock the files given in the argument.  To prevent
     problems with network file locking this is done in an ad hoc
     fashion by attempting to create a symbolic link to the file with
     the name FILE.lockfile.  No other system level functions are used
     for locking, i.e. the file can be accessed and modified by any
     utility that does not use this mechanism.  In particular, the user
     is not prevented from editing the calendar file at the same time
     unless calendar_edit is used.

     Three attempts are made to lock the file before giving up.  If the
     module zsh/zselect is available, the times of the attempts are
     jittered so that multiple instances of the calling function are
     unlikely to retry at the same time.

     The files locked are appended to the array lockfiles, which should
     be local to the caller.

     If all files were successfully locked, status zero is returned,
     else status one.

     This function may be used as a general file locking function,
     although this will only work if only this mechanism is used to
     lock files.

calendar_read
     This is a backend used by various other functions to parse the
     calendar file, which is passed as the only argument.  The array
     calendar_entries is set to the list of events in the file; no
     pruning is done except that ampersands are removed from the start
     of the line.  Each entry may contain multiple lines.

calendar_scandate
     This is a generic function to parse dates and times that may be
     used separately from the calendar system.  The argument is a date
     or time specification as described in *note Calendar File and Date
     Formats::.  The parameter REPLY is set to the number of seconds
     since the epoch corresponding to that date or time.  By default,
     the date and time may occur anywhere within the given argument.

     Returns status zero if the date and time were successfully parsed,
     else one.

     Options:
    -a
          The date and time are anchored to the start of the argument;
          they will not be matched if there is preceding text.

    -A
          The date and time are anchored to both the start and end of
          the argument; they will not be matched if the is any other
          text in the argument.

    -d
          Enable additional debugging output.

    -m
          Minus.  When -R ANCHOR_TIME is also given the relative time is
          calculated backwards from ANCHOR_TIME.

    -r
          The argument passed is to be parsed as a relative time.

    -R ANCHOR_TIME
          The argument passed is to be parsed as a relative time.  The
          time is relative to ANCHOR_TIME, a time in seconds since the
          epoch, and the returned value is the absolute time
          corresponding to advancing ANCHOR_TIME by the relative time
          given.  This allows lengths of months to be correctly taken
          into account.  If the final day does not exist in the given
          month, the last day of the final month is given.  For
          example, if the anchor time is during 31st January 2007 and
          the relative time is 1 month, the final time is the same time
          of day during 28th February 2007.

    -s
          In addition to setting REPLY, set REPLY2 to the remainder of
          the argument after the date and time have been stripped.
          This is empty if the option -A was given.

    -t
          Allow a time with no date specification.  The date is assumed
          to be today.  The behaviour is unspecified if the iron tongue
          of midnight is tolling twelve.


calendar_show
     The function used by default to display events.  It accepts a
     start time and end time for events, both in epoch seconds, and an
     event description.

     The event is always printed to standard output.  If the command
     line editor is active (which will usually be the case) the command
     line will be redisplayed after the output.

     If the parameter DISPLAY is set and the start and end times are
     the same (indicating a scheduled event), the function uses the
     command xmessage to display a window with the event details.



File: zsh.info,  Node: Calendar Bugs,  Prev: Calendar Utility Functions,  Up: Calendar Function System

23.6 Bugs
=========

As the system is based entirely on shell functions (with a little
support from the zsh/datetime module) the mechanisms used are not as
robust as those provided by a dedicated calendar utility.  Consequently
the user should not rely on the shell for vital alerts.

There is no calendar_delete function.

There is no localization support for dates and times, nor any support
for the use of time zones.

Relative periods of months and years do not take into account the
variable number of days.

The calendar_show function is currently hardwired to use xmessage for
displaying alerts on X Window System displays.  This should be
configurable and ideally integrate better with the desktop.

calendar_lockfiles hangs the shell while waiting for a lock on a file.
If called from a scheduled task, it should instead reschedule the event
that caused it.

File: zsh.info,  Node: TCP Function System,  Next: Zftp Function System,  Prev: Calendar Function System,  Up: Top

24 TCP Function System
**********************



24.1 Description
================

A module zsh/net/tcp is provided to provide network I/O over TCP/IP
from within the shell; see its description in *note Zsh Modules:: .
This manual page describes a function suite based on the module.  If
the module is installed, the functions are usually installed at the
same time, in which case they will be available for autoloading in the
default function search path.  In addition to the zsh/net/tcp module,
the zsh/zselect module is used to implement timeouts on read
operations.  For troubleshooting tips, consult the corresponding advice
for the zftp functions described in *note Zftp Function System:: .

There are functions corresponding to the basic I/O operations open,
close, read and send, named tcp_open etc., as well as a function
tcp_expect for pattern match analysis of data read as input.  The
system makes it easy to receive data from and send data to multiple
named sessions at once.  In addition, it can be linked with the shell's
line editor in such a way that input data is automatically shown at the
terminal.  Other facilities available including logging, filtering and
configurable output prompts.

To use the system where it is available, it should be enough to
`autoload -U tcp_open' and run tcp_open as documented below to start a
session.  The tcp_open function will autoload the remaining functions.



* Menu:

* TCP Functions::
* TCP Parameters::
* TCP Examples::
* TCP Bugs::


File: zsh.info,  Node: TCP Functions,  Next: TCP Parameters,  Up: TCP Function System

24.2 TCP User Functions
=======================



24.2.1 Basic I/O
----------------


tcp_open [-qz] HOST PORT [ SESS ]
tcp_open [-qz] [ -s SESS | -l SESS,... ] ...
tcp_open [-qz] [-a FD | -f FD ] [ SESS ]
     Open a new session.  In the first and simplest form, open a TCP
     connection to host HOST at port PORT; numeric and symbolic forms
     are understood for both.

     If SESS is given, this becomes the name of the session which can be
     used to refer to multiple different TCP connections.  If SESS is
     not given, the function will invent a numeric name value (note
     this is _not_ the same as the file descriptor to which the session
     is attached).  It is recommended that session names not include
     `funny' characters, where funny characters are not well-defined
     but certainly do not include alphanumerics or underscores, and
     certainly do include whitespace.

     In the second case, one or more sessions to be opened are given by
     name.  A single session name is given after -s and a
     comma-separated list after -l; both options may be repeated as
     many times as necessary.  A failure to open any session causes
     tcp_open to abort.  The host and port are read from the file
     .ztcp_sessions in the same directory as the user's zsh
     initialisation files, i.e. usually the home directory, but
     $ZDOTDIR if that is set.  The file consists of lines each giving a
     session name and the corresponding host and port, in that order
     (note the session name comes first, not last), separated by
     whitespace.

     The third form allows passive and fake TCP connections.  If the
     option -a is used, its argument is a file descriptor open for
     listening for connections.  No function front-end is provided to
     open such a file descriptor, but a call to `ztcp -l PORT' will
     create one with the file descriptor stored in the parameter
     $REPLY.  The listening port can be closed with `ztcp -c FD'.  A
     call to `tcp_open -a FD' will block until a remote TCP connection
     is made to PORT on the local machine.  At this point, a session is
     created in the usual way and is largely indistinguishable from an
     active connection created with one of the first two forms.

     If the option -f is used, its argument is a file descriptor which
     is used directly as if it were a TCP session.  How well the
     remainder of the TCP function system copes with this depends on
     what actually underlies this file descriptor.  A regular file is
     likely to be unusable; a FIFO (pipe) of some sort will work
     better, but note that it is not a good idea for two different
     sessions to attempt to read from the same FIFO at once.

     If the option -q is given with any of the three forms, tcp_open
     will not print informational messages, although it will in any
     case exit with an appropriate status.

     If the line editor (zle) is in use, which is typically the case if
     the shell is interactive, tcp_open installs a handler inside zle
     which will check for new data at the same time as it checks for
     keyboard input.  This is convenient as the shell consumes no CPU
     time while waiting; the test is performed by the operating system.
     Giving the option -z to any of the forms of tcp_open prevents the
     handler from being installed, so data must be read explicitly.
     Note, however, this is not necessary for executing complete sets
     of send and read commands from a function, as zle is not active at
     this point.  Generally speaking, the handler is only active when
     the shell is waiting for input at a command prompt or in the vared
     builtin.  The option has no effect if zle is not active; `[[ -o
     zle]]' will test for this.

     The first session to be opened becomes the current session and
     subsequent calls to tcp_open do not change it.  The current
     session is stored in the parameter $TCP_SESS; see below for more
     detail about the parameters used by the system.

     The function tcp_on_open, if defined, is called when a session is
     opened.  See the description below.

tcp_close [-qn] [ -a | -l SESS,... | SESS ... ]
     Close the named sessions, or the current session if none is given,
     or all open sessions if -a is given.  The options -l and -s are
     both handled for consistency with tcp_open, although the latter is
     redundant.

     If the session being closed is the current one, $TCP_SESS is unset,
     leaving no current session, even if there are other sessions still
     open.

     If the session was opened with tcp_open -f, the file descriptor is
     closed so long as it is in the range 0 to 9 accessible directly
     from the command line.  If the option -n is given, no attempt will
     be made to close file descriptors in this case.  The -n option is
     not used for genuine ztcp session; the file descriptors are always
     closed with the session.

     If the option -q is given, no informational messages will be
     printed.

tcp_read [-bdq] [ -t TO ] [ -T TO ]
[ -a | -u FD ... | -l SESS,... | -s SESS ...]
     Perform a read operation on the current session, or on a list of
     sessions if any are given with -u, -l or -s, or all open sessions
     if the option -a is given.  Any of the -u, -l or -s options may be
     repeated or mixed together.  The -u option specifies a file
     descriptor directly (only those managed by this system are
     useful), the other two specify sessions as described for tcp_open
     above.

     The function checks for new data available on all the sessions
     listed.  Unless the -b option is given, it will not block waiting
     for new data.  Any one line of data from any of the available
     sessions will be read, stored in the parameter $TCP_LINE, and
     displayed to standard output unless $TCP_SILENT contains a
     non-empty string.  When printed to standard output the string
     $TCP_PROMPT will be shown at the start of the line; the default
     form for this includes the name of the session being read.  See
     below for more information on these parameters.  In this mode,
     tcp_read can be called repeatedly until it returns status 2 which
     indicates all pending input from all specified sessions has been
     handled.

     With the option -b, equivalent to an infinite timeout, the function
     will block until a line is available to read from one of the
     specified sessions.  However, only a single line is returned.

     The option -d indicates that all pending input should be drained.
     In this case tcp_read may process multiple lines in the manner
     given above; only the last is stored in $TCP_LINE, but the
     complete set is stored in the array $tcp_lines.  This is cleared
     at the start of each call to tcp_read.

     The options -t and -T specify a timeout in seconds, which may be a
     floating point number for increased accuracy.  With -t the timeout
     is applied before each line read.  With -T, the timeout applies to
     the overall operation, possibly including multiple read operations
     if the option -d is present; without this option, there is no
     distinction between -t and -T.

     The function does not print informational messages, but if the
     option -q is given, no error message is printed for a non-existent
     session.

     A return status of 2 indicates a timeout or no data to read.  Any
     other non-zero return status indicates some error condition.

     See tcp_log for how to control where data is sent by tcp_read.

tcp_send [-cnq] [ -s SESS | -l SESS,... ] DATA ...
tcp_send [-cnq] -a DATA ...
     Send the supplied data strings to all the specified sessions in
     turn.  The underlying operation differs little from a `print -r'
     to the session's file descriptor, although it attempts to prevent
     the shell from dying owing to a SIGPIPE caused by an attempt to
     write to a defunct session.

     The option -c causes tcp_send to behave like cat.  It reads lines
     from standard input until end of input and sends them in turn to
     the specified session(s) exactly as if they were given as DATA
     arguments to individual tcp_send commands.

     The option -n prevents tcp_send from putting a newline at the end
     of the data strings.

     The remaining options all behave as for tcp_read.

     The data arguments are not further processed once they have been
     passed to tcp_send; they are simply passed down to print -r.

     If the parameter $TCP_OUTPUT is a non-empty string and logging is
     enabled then the data sent to each session will be echoed to the
     log file(s) with $TCP_OUTPUT in front where appropriate, much in
     the manner of $TCP_PROMPT.



24.2.2 Session Management
-------------------------


tcp_alias [-q] ALIAS=SESS ...
tcp_alias [-q] [ ALIAS ] ...
tcp_alias -d [-q] ALIAS ...
     This function is not particularly well tested.

     The first form creates an alias for a session name; ALIAS can then
     be used to refer to the existing session SESS.  As many aliases
     may be listed as required.

     The second form lists any aliases specified, or all aliases if
     none.

     The third form deletes all the aliases listed.  The underlying
     sessions are not affected.

     The option -q suppresses an inconsistently chosen subset of error
     messages.

tcp_log [-asc] [ -n | -N ] [ LOGFILE ]
     With an argument LOGFILE, all future input from tcp_read will be
     logged to the named file.  Unless -a (append) is given, this file
     will first be truncated or created empty.  With no arguments, show
     the current status of logging.

     With the option -s, per-session logging is enabled.  Input from
     tcp_read is output to the file LOGFILE.SESS.  As the session is
     automatically discriminated by the filename, the contents are raw
     (no $TCP_PROMPT).  The option  -a applies as above.  Per-session
     logging and logging of all data in one file are not mutually
     exclusive.

     The option -c closes all logging, both complete and per-session
     logs.

     The options -n and -N respectively turn off or restore output of
     data read by tcp_read to standard output; hence `tcp_log -cn' turns
     off all output by tcp_read.

     The function is purely a convenient front end to setting the
     parameters $TCP_LOG, $TCP_LOG_SESS, $TCP_SILENT, which are
     described below.

tcp_rename OLD NEW
     Rename session OLD to session NEW.  The old name becomes invalid.

tcp_sess [ SESS [ COMMAND  ... ] ]
     With no arguments, list all the open sessions and associated file
     descriptors.  The current session is marked with a star.  For use
     in functions, direct access to the parameters $tcp_by_name,
     $tcp_by_fd and $TCP_SESS is probably more convenient; see below.

     With a SESS argument, set the current session to SESS.  This is
     equivalent to changing $TCP_SESS directly.

     With additional arguments, temporarily set the current session
     while executing the string command ....  The first argument is
     re-evaluated so as to expand aliases etc., but the remaining
     arguments are passed through as the appear to tcp_sess.  The
     original session is restored when tcp_sess exits.



24.2.3 Advanced I/O
-------------------


tcp_command SEND-OPTIONS ... SEND-ARGUMENTS ...
     This is a convenient front-end to tcp_send.  All arguments are
     passed to tcp_send, then the function pauses waiting for data.
     While data is arriving at least every $TCP_TIMEOUT (default 0.3)
     seconds, data is handled and printed out according to the current
     settings.  Status 0 is always returned.

     This is generally only useful for interactive use, to prevent the
     display becoming fragmented by output returned from the
     connection.  Within a programme or function it is generally better
     to handle reading data by a more explicit method.

tcp_expect [ -q ] [ -p VAR ] [ -t  TO | -T TO]
    [ -a | -s SESS ... | -l SESS,... ] PATTERN ...
     Wait for input matching any of the given PATTERNs from any of the
     specified sessions.  Input is ignored until an input line matches
     one of the given patterns; at this point status zero is returned,
     the matching line is stored in $TCP_LINE, and the full set of
     lines read during the call to tcp_expect is stored in the array
     $tcp_expect_lines.

     Sessions are specified in the same way as tcp_read: the default is
     to use the current session, otherwise the sessions specified by -a,
     -s, or -l are used.

     Each PATTERN is a standard zsh extended-globbing pattern; note
     that it needs to be quoted to avoid it being expanded immediately
     by filename generation.  It must match the full line, so to match
     a substring there must be a `*' at the start and end.  The line
     matched against includes the $TCP_PROMPT added by tcp_read.  It is
     possible to include the globbing flags `#b' or `#m' in the
     patterns to make backreferences available in the parameters
     $MATCH, $match, etc., as described in the base zsh documentation
     on pattern matching.

     Unlike tcp_read, the default behaviour of tcp_expect is to block
     indefinitely until the required input is found.  This can be
     modified by specifying a timeout with -t or -T; these function as
     in tcp_read, specifying a per-read or overall timeout,
     respectively, in seconds, as an integer or floating-point number.
     As tcp_read, the function returns status 2 if a timeout occurs.

     The function returns as soon as any one of the patterns given
     match.  If the caller needs to know which of the patterns matched,
     the option -p VAR can be used; on return, $var is set to the
     number of the pattern using ordinary zsh indexing, i.e. the first
     is 1, and so on.  Note the absence of a `$' in front of VAR.  To
     avoid clashes, the parameter cannot begin with `_expect'.

     The option -q is passed directly down to tcp_read.

     As all input is done via tcp_read, all the usual rules about
     output of lines read apply.  One exception is that the parameter
     $tcp_lines will only reflect the line actually matched by
     tcp_expect; use $tcp_expect_lines for the full set of lines read
     during the function call.

tcp_proxy
     This is a simple-minded function to accept a TCP connection and
     execute a command with I/O redirected to the connection.  Extreme
     caution should be taken as there is no security whatsoever and
     this can leave your computer open to the world.  Ideally, it
     should only be used behind a firewall.

     The first argument is a TCP port on which the function will listen.

     The remaining arguments give a command and its arguments to
     execute with standard input, standard output and standard error
     redirected to the file descriptor on which the TCP session has
     been accepted.  If no command is given, a new zsh is started.
     This gives everyone on your network direct access to your account,
     which in many cases will be a bad thing.

     The command is run in the background, so tcp_proxy can then accept
     new connections.  It continues to accept new connections until
     interrupted.

tcp_spam [-ertv] [ -a | -s  SESS | -l SESS,... ] CMD ...
     Execute `CMD ...' for each session in turn.  Note this executes
     the command and arguments; it does not send the command line as
     data unless the -t (transmit) option is given.

     The sessions may be selected explicitly with the standard -a, -s or
     -l options, or may be chosen implicitly.  If none of the three
     options is given the rules are: first, if the array $tcp_spam_list
     is set, this is taken as the list of sessions, otherwise all
     sessions are taken.  Second, any sessions given in the array
     $tcp_no_spam_list are removed from the list of sessions.

     Normally, any sessions added by the `-a' flag or when all sessions
     are chosen implicitly are spammed in alphabetic order; sessions
     given by the $tcp_spam_list array or on the command line are
     spammed in the order given.  The -r flag reverses the order
     however it was arrived it.

     The -v flag specifies that a $TCP_PROMPT will be output before each
     session.  This is output after any modification to TCP_SESS by the
     user-defined tcp_on_spam function described below.  (Obviously that
     function is able to generate its own output.)

     If the option -e is present, the line given as CMD ... is executed
     using eval, otherwise it is executed without any further
     processing.

tcp_talk
     This is a fairly simple-minded attempt to force input to the line
     editor to go straight to the default TCP_SESSION.

     An escape string, $TCP_TALK_ESCAPE, default `:', is used to allow
     access to normal shell operation.  If it is on its own at the
     start of the line, or followed only by whitespace, the line editor
     returns to normal operation.  Otherwise, the string and any
     following whitespace are skipped and the remainder of the line
     executed as shell input without any change of the line editor's
     operating mode.

     The current implementation is somewhat deficient in terms of use
     of the command history.  For this reason, many users will prefer
     to use some form of alternative approach for sending data easily
     to the current session.  One simple approach is to alias some
     special character (such as `%') to `tcp_command --'.

tcp_wait
     The sole argument is an integer or floating point number which
     gives the seconds to delay.  The shell will do nothing for that
     period except wait for input on all TCP sessions by calling
     tcp_read -a.  This is similar to the interactive behaviour at the
     command prompt when zle handlers are installed.



24.2.4 `One-shot' file transfer
-------------------------------


tcp_point PORT
tcp_shoot HOST PORT
     This pair of functions provide a simple way to transfer a file
     between two hosts within the shell.  Note, however, that bulk data
     transfer is currently done using cat.  tcp_point reads any data
     arriving at PORT and sends it to standard output; tcp_shoot
     connects to PORT on HOST and sends its standard input.  Any unused
     PORT may be used; the standard mechanism for picking a port is to
     think of a random four-digit number above 1024 until one works.

     To transfer a file from host woodcock to host springes, on
     springes:


          tcp_point 8091 >output_file

     and on woodcock:


          tcp_shoot springes 8091 <input_file

     As these two functions do not require tcp_open to set up a TCP
     connection first, they may need to be autoloaded separately.



24.3 TCP User-defined Functions
===============================

Certain functions, if defined by the user, will be called by the
function system in certain contexts.  This facility depends on the
module zsh/parameter, which is usually available in interactive shells
as the completion system depends on it.  None of the functions need be
defined; they simply provide convenient hooks when necessary.

Typically, these are called after the requested action has been taken,
so that the various parameters will reflect the new state.


tcp_on_alias ALIAS FD
     When an alias is defined, this function will be called with two
     arguments: the name of the alias, and the file descriptor of the
     corresponding session.

tcp_on_awol SESS FD
     If the function tcp_fd_handler is handling input from the line
     editor and detects that the file descriptor is no longer reusable,
     by default it removes it from the list of file descriptors handled
     by this method and prints a message.  If the function tcp_on_awol
     is defined it is called immediately before this point.  It may
     return status 100, which indicates that the normal handling should
     still be performed; any other return status indicates that no
     further action should be taken and the tcp_fd_handler should return
     immediately with the given status.  Typically the action of
     tcp_on_awol will be to close the session.

     The variable TCP_INVALIDATE_ZLE will be a non-empty string if it is
     necessary to invalidate the line editor display using `zle -I'
     before printing output from the function.

     (`AWOL' is military jargon for `absent without leave' or some
     variation.  It has no pre-existing technical meaning known to the
     author.)

tcp_on_close SESS FD
     This is called with the name of a session being closed and the file
     descriptor which corresponded to that session.  Both will be
     invalid by the time the function is called.

tcp_on_open SESS FD
     This is called after a new session has been defined with the
     session name and file descriptor as arguments.  If it returns a
     non-zero status, opening the session is assumed to fail and the
     session is closed again; however, tcp_open will continue to
     attempt to open any remaining sessions given on the command line.

tcp_on_rename OLDSESS FD NEWSESS
     This is called after a session has been renamed with the three
     arguments old session name, file descriptor, new session name.

tcp_on_spam SESS COMMAND ...
     This is called once for each session spammed, just _before_ a
     command is executed for a session by tcp_spam.  The arguments are
     the session name followed by the command list to be executed.  If
     tcp_spam was called with the option -t, the first command will be
     tcp_send.

     This function is called after $TCP_SESS is set to reflect the
     session to be spammed, but before any use of it is made.  Hence it
     is possible to alter the value of $TCP_SESS within this function.
     For example, the session arguments to tcp_spam could include extra
     information to be stripped off and processed in tcp_on_spam.

     If the function sets the parameter $REPLY to `done', the command
     line is not executed; in addition, no prompt is printed for the -v
     option to tcp_spam.

tcp_on_unalias ALIAS FD
     This is called with the name of an alias and the corresponding
     session's file descriptor after an alias has been deleted.



24.4 TCP Utility Functions
==========================

The following functions are used by the TCP function system but will
rarely if ever need to be called directly.


tcp_fd_handler
     This is the function installed by tcp_open for handling input from
     within the line editor, if that is required.  It is in the format
     documented for the builtin `zle -F' in *note Zle Builtins:: .

     While active, the function sets the parameter TCP_HANDLER_ACTIVE
     to 1.  This allows shell code called internally (for example, by
     setting tcp_on_read) to tell if is being called when the shell is
     otherwise idle at the editor prompt.

tcp_output [ -q ] -P PROMPT -F FD -S SESS
     This function is used for both logging and handling output to
     standard output, from within tcp_read and (if $TCP_OUTPUT is set)
     tcp_send.

     The PROMPT to use is specified by -P; the default is the empty
     string.  It can contain:
    %c
          Expands to 1 if the session is the current session, otherwise
          0.  Used with ternary expressions such as `%(c.-.+)' to
          output `+' for the current session and `-' otherwise.

    %f
          Replaced by the session's file descriptor.

    %s
          Replaced by the session name.

    %%
          Replaced by a single `%'.


     The option -q suppresses output to standard output, but not to any
     log files which are configured.

     The -S and -F options are used to pass in the session name and file
     descriptor for possible replacement in the prompt.



File: zsh.info,  Node: TCP Parameters,  Next: TCP Examples,  Prev: TCP Functions,  Up: TCP Function System

24.5 TCP User Parameters
========================

Parameters follow the usual convention that uppercase is used for
scalars and integers, while lowercase is used for normal and
associative array.  It is always safe for user code to read these
parameters.  Some parameters may also be set; these are noted
explicitly.  Others are included in this group as they are set by the
function system for the user's benefit, i.e. setting them is typically
not useful but is benign.

It is often also useful to make settable parameters local to a function.
For example, `local TCP_SILENT=1' specifies that data read during the
function call will not be printed to standard output, regardless of the
setting outside the function.  Likewise, `local TCP_SESS=SESS' sets a
session for the duration of a function, and `local TCP_PROMPT='
specifies that no prompt is used for input during the function.


tcp_expect_lines
     Array.  The set of lines read during the last call to tcp_expect,
     including the last ($TCP_LINE).

tcp_filter
     Array. May be set directly.  A set of extended globbing patterns
     which, if matched in tcp_output, will cause the line not to be
     printed to standard output.  The patterns should be defined as
     described for the arguments to tcp_expect.  Output of line to log
     files is not affected.

TCP_HANDLER_ACTIVE
     Scalar.  Set to 1 within tcp_fd_handler to indicate to functions
     called recursively that they have been called during an editor
     session.  Otherwise unset.

TCP_LINE
     The last line read by tcp_read, and hence also tcp_expect.

TCP_LINE_FD
     The file descriptor from which $TCP_LINE was read.
     ${tcp_by_fd[$TCP_LINE_FD]} will give the corresponding session
     name.

tcp_lines
     Array. The set of lines read during the last call to tcp_read,
     including the last ($TCP_LINE).

TCP_LOG
     May be set directly, although it is also controlled by tcp_log.
     The name of a file to which output from all sessions will be sent.
     The output is proceeded by the usual $TCP_PROMPT.  If it is not an
     absolute path name, it will follow the user's current directory.

TCP_LOG_SESS
     May be set directly, although it is also controlled by tcp_log.
     The prefix for a set of files to which output from each session
     separately will be sent; the full filename is ${TCP_LOG_SESS}.SESS.
     Output to each file is raw; no prompt is added.  If it is not an
     absolute path name, it will follow the user's current directory.

tcp_no_spam_list
     Array.  May be set directly.  See tcp_spam for how this is used.

TCP_OUTPUT
     May be set directly.  If a non-empty string, any data sent to a
     session by tcp_send will be logged.  This parameter gives the
     prompt to be used in a file specified by $TCP_LOG but not in a
     file generated from $TCP_LOG_SESS.  The prompt string has the same
     format as TCP_PROMPT and the same rules for its use apply.

TCP_PROMPT
     May be set directly.  Used as the prefix for data read by tcp_read
     which is printed to standard output or to the log file given by
     $TCP_LOG, if any.  Any `%s', `%f' or `%%' occurring in the string
     will be replaced by the name of the session, the session's
     underlying file descriptor, or a single `%', respectively.  The
     expression `%c' expands to 1 if the session being read is the
     current session, else 0; this is most useful in ternary
     expressions such as `%(c.-.+)' which outputs `+' if the session is
     the current one, else `-'.

TCP_READ_DEBUG
     May be set directly.  If this has non-zero length, tcp_read will
     give some limited diagnostics about data being read.

TCP_SECONDS_START
     This value is created and initialised to zero by tcp_open.

     The functions tcp_read and tcp_expect use the shell's SECONDS
     parameter for their own timing purposes.  If that parameter is not
     of floating point type on entry to one of the functions, it will
     create a local parameter SECONDS which is floating point and set
     the parameter TCP_SECONDS_START to the previous value of $SECONDS.
     If the parameter is already floating point, it is used without a
     local copy being created and TCP_SECONDS_START is not set.  As the
     global value is zero, the shell elapsed time is guaranteed to be
     the sum of $SECONDS and $TCP_SECONDS_START.

     This can be avoided by setting SECONDS globally to a floating point
     value using `typeset -F SECONDS'; then the TCP functions will never
     make a local copy and never set TCP_SECONDS_START to a non-zero
     value.

TCP_SESS
     May be set directly.  The current session; must refer to one of the
     sessions established by tcp_open.

TCP_SILENT
     May be set directly, although it is also controlled by tcp_log.
     If of non-zero length, data read by tcp_read will not be written to
     standard output, though may still be written to a log file.

tcp_spam_list
     Array.  May be set directly.  See the description of the function
     tcp_spam for how this is used.

TCP_TALK_ESCAPE
     May be set directly.  See the description of the function tcp_talk
     for how this is used.

TCP_TIMEOUT
     May be set directly.  Currently this is only used by the function
     tcp_command, see above.



24.6 TCP User-defined Parameters
================================

The following parameters are not set by the function system, but have a
special effect if set by the user.


tcp_on_read
     This should be an associative array; if it is not, the behaviour is
     undefined.  Each key is the name of a shell function or other
     command, and the corresponding value is a shell pattern (using
     EXTENDED_GLOB).  Every line read from a TCP session directly or
     indirectly using tcp_read (which includes lines read by
     tcp_expect) is compared against the pattern.  If the line matches,
     the command given in the key is called with two arguments: the
     name of the session from which the line was read, and the line
     itself.

     If any function called to handle a line returns a non-zero status,
     the line is not output.  Thus a tcp_on_read handler containing only
     the instruction `return 1' can be used to suppress output of
     particular lines (see, however, tcp_filter above).  However, the
     line is still stored in TCP_LINE and tcp_lines; this occurs after
     all tcp_on_read processing.



24.7 TCP Utility Parameters
===========================

These parameters are controlled by the function system; they may be read
directly, but should not usually be set by user code.


tcp_aliases
     Associative array.  The keys are the names of sessions established
     with tcp_open; each value is a space-separated list of aliases
     which refer to that session.

tcp_by_fd
     Associative array.  The keys are session file descriptors; each
     value is the name of that session.

tcp_by_name
     Associative array.  The keys are the names of sessions; each value
     is the file descriptor associated with that session.



File: zsh.info,  Node: TCP Examples,  Next: TCP Bugs,  Prev: TCP Parameters,  Up: TCP Function System

24.8 TCP Examples
=================

Here is a trivial example using a remote calculator.

TO create a calculator server on port 7337 (see the dc manual page for
quite how infuriating the underlying command is):


     tcp_proxy 7337 dc

To connect to this from the same host with a session also named `dc':


     tcp_open localhost 7337 dc

To send a command to the remote session and wait a short while for
output (assuming dc is the current session):


     tcp_command 2 4 + p

To close the session:


     tcp_close

The tcp_proxy needs to be killed to be stopped.  Note this will not
usually kill any connections which have already been accepted, and also
that the port is not immediately available for reuse.

The following chunk of code puts a list of sessions into an xterm
header, with the current session followed by a star.


     print -n "\033]2;TCP:" ${(k)tcp_by_name:/$TCP_SESS/$TCP_SESS\*} "\a"


File: zsh.info,  Node: TCP Bugs,  Prev: TCP Examples,  Up: TCP Function System

24.9 TCP Bugs
=============

The function tcp_read uses the shell's normal read builtin.  As this
reads a complete line at once, data arriving without a terminating
newline can cause the function to block indefinitely.

Though the function suite works well for interactive use and for data
arriving in small amounts, the performance when large amounts of data
are being exchanged is likely to be extremely poor.

File: zsh.info,  Node: Zftp Function System,  Next: User Contributions,  Prev: TCP Function System,  Up: Top

25 Zftp Function System
***********************



25.1 Description
================

This describes the set of shell functions supplied with the source
distribution as an interface to the zftp builtin command, allowing you
to perform FTP operations from the shell command line or within
functions or scripts.  The interface is similar to a traditional FTP
client (e.g. the ftp command itself, see man page ftp(1)), but as it is
entirely done within the shell all the familiar completion, editing and
globbing features, and so on, are present, and macros are particularly
simple to write as they are just ordinary shell functions.

The prerequisite is that the zftp command, as described in *note The
zsh/zftp Module:: , must be available in the version of zsh installed
at your site.  If the shell is configured to load new commands at run
time, it probably is: typing `zmodload zsh/zftp' will make sure (if
that runs silently, it has worked).  If this is not the case, it is
possible zftp was linked into the shell anyway: to test this, type
`which zftp' and if zftp is available you will get the message `zftp:
shell built-in command'.

Commands given directly with zftp builtin may be interspersed between
the functions in this suite; in a few cases, using zftp directly may
cause some of the status information stored in shell parameters to
become invalid.  Note in particular the description of the variables
$ZFTP_TMOUT, $ZFTP_PREFS and $ZFTP_VERBOSE for zftp.



* Menu:

* Installation::
* Zftp Functions::
* Miscellaneous Features::


File: zsh.info,  Node: Installation,  Next: Zftp Functions,  Up: Zftp Function System

25.2 Installation
=================

You should make sure all the functions from the Functions/Zftp
directory of the source distribution are available; they all begin with
the two letters `zf'.  They may already have been installed on your
system; otherwise, you will need to find them and copy them.  The
directory should appear as one of the elements of the $fpath array
(this should already be the case if they were installed), and at least
the function zfinit should be autoloaded; it will autoload the rest.
Finally, to initialize the use of the system you need to call the
zfinit function.  The following code in your .zshrc will arrange for
this; assume the functions are stored in the directory ~/myfns:


     fpath=(~/myfns $fpath)
     autoload -U zfinit
     zfinit

Note that zfinit assumes you are using the zmodload method to load the
zftp command.  If it is already built into the shell, change zfinit to
zfinit -n.  It is helpful (though not essential) if the call to zfinit
appears after any code to initialize the new completion system, else
unnecessary compctl commands will be given.



File: zsh.info,  Node: Zftp Functions,  Next: Miscellaneous Features,  Prev: Installation,  Up: Zftp Function System

25.3 Functions
==============

The sequence of operations in performing a file transfer is essentially
the same as that in a standard FTP client.  Note that, due to a quirk
of the shell's getopts builtin, for those functions that handle options
you must use `--' rather than `-' to ensure the remaining arguments are
treated literally (a single `-' is treated as an argument).



25.3.1 Opening a connection
---------------------------


zfparams [ HOST [ USER [ PASSWORD ... ] ] ]
     Set or show the parameters for a future zfopen with no arguments.
     If no arguments are given, the current parameters are displayed
     (the password will be shown as a line of asterisks).  If a host is
     given, and either the USER or PASSWORD is not, they will be
     prompted for; also, any parameter given as `?' will be prompted
     for, and if the `?' is followed by a string, that will be used as
     the prompt.  As zfopen calls zfparams to store the parameters,
     this usually need not be called directly.

     A single argument `-' will delete the stored parameters.  This will
     also cause the memory of the last directory (and so on) on the
     other host to be deleted.

zfopen [ -1 ] [ HOST [ USER [ PASSWORD [ ACCOUNT ] ] ] ]
     If HOST is present, open a connection to that host under username
     USER with password PASSWORD (and, on the rare occasions when it is
     necessary, account ACCOUNT).  If a necessary parameter is missing
     or given as `?' it will be prompted for.  If HOST is not present,
     use a previously stored set of parameters.

     If the command was successful, and the terminal is compatible with
     xterm or is sun-cmd, a summary will appear in the title bar,
     giving the local host:directory and the remote host:directory;
     this is handled by the function zftp_chpwd, described below.

     Normally, the HOST, USER and PASSWORD are internally recorded for
     later re-opening, either by a zfopen with no arguments, or
     automatically (see below).  With the option `-1', no information is
     stored.  Also, if an open command with arguments failed, the
     parameters will not be retained (and any previous parameters will
     also be deleted).  A zfopen on its own, or a zfopen -1, never
     alters the stored parameters.

     Both zfopen and zfanon (but not zfparams) understand URLs of the
     form ftp://HOST/PATH... as meaning to connect to the HOST, then
     change directory to PATH (which must be a directory, not a file).
     The `ftp://' can be omitted; the trailing `/' is enough to trigger
     recognition of the PATH.  Note prefixes other than `ftp:' are not
     recognized, and that all characters after the first slash beyond
     HOST are significant in PATH.

zfanon [ -1 ] HOST
     Open a connection HOST for anonymous FTP.  The username used is
     `anonymous'.  The password (which will be reported the first time)
     is generated as USER@HOST; this is then stored in the shell
     parameter $EMAIL_ADDR which can alternatively be set manually to a
     suitable string.



25.3.2 Directory management
---------------------------


zfcd [ DIR ]
zfcd -
zfcd OLD NEW
     Change the current directory on the remote server:  this is
     implemented to have many of the features of the shell builtin cd.

     In the first form with DIR present, change to the directory DIR.
     The command `zfcd ..' is treated specially, so is guaranteed to
     work on non-UNIX servers (note this is handled internally by
     zftp).  If DIR is omitted, has the effect of `zfcd ~'.

     The second form changes to the directory previously current.

     The third form attempts to change the current directory by
     replacing the first occurrence of the string OLD with the string
     NEW in the current directory.

     Note that in this command, and indeed anywhere a remote filename is
     expected, the string which on the local host corresponds to `~' is
     converted back to a `~' before being passed to the remote machine.
     This is convenient because of the way expansion is performed on
     the command line before zfcd receives a string.  For example,
     suppose the command is `zfcd ~/foo'.  The shell will expand this
     to a full path such as `zfcd /home/user2/pws/foo'.  At this stage,
     zfcd recognises the initial path as corresponding to `~' and will
     send the directory to the remote host as ~/foo, so that the `~'
     will be expanded by the server to the correct remote host
     directory.  Other named directories of the form `~name' are not
     treated in this fashion.

zfhere
     Change directory on the remote server to the one corresponding to
     the current local directory, with special handling of `~' as in
     zfcd.  For example, if the current local directory is ~/foo/bar,
     then zfhere performs the effect of `zfcd ~/foo/bar'.

zfdir [ -rfd ] [ - ] [ DIR-OPTIONS ] [ DIR ]
     Produce a long directory listing.  The arguments DIR-OPTIONS and
     DIR are passed directly to the server and their effect is
     implementation dependent, but specifying a particular remote
     directory DIR is usually possible.  The output is passed through a
     pager given by the environment variable $PAGER, or `more' if that
     is not set.

     The directory is usually cached for re-use.  In fact, two caches
     are maintained.  One is for use when there is no DIR-OPTIONS or
     DIR, i.e. a full listing of the current remote directory; it is
     flushed when the current remote directory changes.  The other is
     kept for repeated use of zfdir with the same arguments; for
     example, repeated use of `zfdir /pub/gnu' will only require the
     directory to be retrieved on the first call.  Alternatively, this
     cache can be re-viewed with the -r option.  As relative
     directories will confuse zfdir, the -f option can be used to force
     the cache to be flushed before the directory is listed.  The
     option -d will delete both caches without showing a directory
     listing; it will also delete the cache of file names in the
     current remote directory, if any.

zfls [ LS-OPTIONS ] [ DIR ]
     List files on the remote server.  With no arguments, this will
     produce a simple list of file names for the current remote
     directory.  Any arguments are passed directly to the server.  No
     pager and no caching is used.



25.3.3 Status commands
----------------------


zftype [ TYPE ]
     With no arguments, show the type of data to be transferred,
     usually ASCII or binary.  With an argument, change the type: the
     types `A' or `ASCII' for ASCII data and `B' or `BINARY', `I' or
     `IMAGE' for binary data are understood case-insensitively.

zfstat [ -v ]
     Show the status of the current or last connection, as well as the
     status of some of zftp's status variables.  With the -v option, a
     more verbose listing is produced by querying the server for its
     version of events, too.



25.3.4 Retrieving files
-----------------------

The commands for retrieving files all take at least two options. -G
suppresses remote filename expansion which would otherwise be performed
(see below for a more detailed description of that).  -t attempts to
set the modification time of the local file to that of the remote file:
see the description of the function zfrtime below for more information.


zfget [ -Gtc ] FILE1 ...
     Retrieve all the listed files FILE1 ... one at a time from the
     remote server.  If a file contains a `/', the full name is passed
     to the remote server, but the file is stored locally under the
     name given by the part after the final `/'.  The option -c (cat)
     forces all files to be sent as a single stream to standard output;
     in this case the -t option has no effect.

zfuget [ -Gvst ] FILE1 ...
     As zfget, but only retrieve files where the version on the remote
     server is newer (has a later modification time), or where the
     local file does not exist.  If the remote file is older but the
     files have different sizes, or if the sizes are the same but the
     remote file is newer, the user will usually be queried.  With the
     option -s, the command runs silently and will always retrieve the
     file in either of those two cases.  With the option -v, the
     command prints more information about the files while it is
     working out whether or not to transfer them.

zfcget [ -Gt ] FILE1 ...
     As zfget, but if any of the local files exists, and is shorter than
     the corresponding remote file, the command assumes that it is the
     result of a partially completed transfer and attempts to transfer
     the rest of the file.  This is useful on a poor connection which
     keeps failing.

     Note that this requires a commonly implemented, but non-standard,
     version of the FTP protocol, so is not guaranteed to work on all
     servers.

zfgcp [ -Gt ] REMOTE-FILE LOCAL-FILE
zfgcp [ -Gt ] RFILE1 ... LDIR
     This retrieves files from the remote server with arguments behaving
     similarly to the cp command.

     In the first form, copy REMOTE-FILE from the server to the local
     file LOCAL-FILE.

     In the second form, copy all the remote files RFILE1 ... into the
     local directory LDIR retaining the same basenames.  This assumes
     UNIX directory semantics.



25.3.5 Sending files
--------------------


zfput [ -r ] FILE1 ...
     Send all the FILE1 ... given separately to the remote server.  If a
     filename contains a `/', the full filename is used locally to find
     the file, but only the basename is used for the remote file name.

     With the option -r, if any of the FILES are directories they are
     sent recursively with all their subdirectories, including files
     beginning with `.'.  This requires that the remote machine
     understand UNIX file semantics, since `/' is used as a directory
     separator.

zfuput [ -vs ] FILE1 ...
     As zfput, but only send files which are newer than their local
     equivalents, or if the remote file does not exist.  The logic is
     the same as for zfuget, but reversed between local and remote
     files.

zfcput FILE1 ...
     As zfput, but if any remote file already exists and is shorter
     than the local equivalent, assume it is the result of an
     incomplete transfer and send the rest of the file to append to the
     existing part.  As the FTP append command is part of the standard
     set, this is in principle more likely to work than zfcget.

zfpcp LOCAL-FILE REMOTE-FILE
zfpcp LFILE1 ... RDIR
     This sends files to the remote server with arguments behaving
     similarly to the cp command.

     With two arguments, copy LOCAL-FILE to the server as REMOTE-FILE.

     With more than two arguments, copy all the local files LFILE1 ...
     into the existing remote directory RDIR retaining the same
     basenames.  This assumes UNIX directory semantics.

     A problem arises if you attempt to use zfpcp LFILE1 RDIR, i.e. the
     second form of copying but with two arguments, as the command has
     no simple way of knowing if RDIR corresponds to a directory or a
     filename.  It attempts to resolve this in various ways.  First, if
     the RDIR argument is `.' or `..' or ends in a slash, it is assumed
     to be a directory.  Secondly, if the operation of copying to a
     remote file in the first form failed, and the remote server sends
     back the expected failure code 553 and a reply including the
     string `Is a directory', then zfpcp will retry using the second
     form.



25.3.6 Closing the connection
-----------------------------


zfclose
     Close the connection.



25.3.7 Session management
-------------------------


zfsession [ -lvod ] [ SESSNAME ]
     Allows you to manage multiple FTP sessions at once.  By default,
     connections take place in a session called `default'; by giving the
     command `zfsession SESSNAME' you can change to a new or existing
     session with a name of your choice.  The new session remembers its
     own connection, as well as associated shell parameters, and also
     the host/user parameters set by zfparams.  Hence you can have
     different sessions set up to connect to different hosts, each
     remembering the appropriate host, user and password.

     With no arguments, zfsession prints the name of the current
     session; with the option -l it lists all sessions which currently
     exist, and with the option -v it gives a verbose list showing the
     host and directory for each session, where the current session is
     marked with an asterisk.  With -o, it will switch to the most
     recent previous session.

     With -d, the given session (or else the current one) is removed;
     everything to do with it is completely forgotten.  If it was the
     only session, a new session called `default' is created and made
     current.  It is safest not to delete sessions while background
     commands using zftp are active.

zftransfer SESS1:FILE1 SESS2:FILE2
     Transfer files between two sessions; no local copy is made.  The
     file is read from the session SESS1 as FILE1 and written to session
     SESS2 as file FILE2; FILE1 and FILE2 may be relative to the
     current directories of the session.  Either SESS1 or SESS2 may be
     omitted (though the colon should be retained if there is a
     possibility of a colon appearing in the file name) and defaults to
     the current session; FILE2 may be omitted or may end with a slash,
     in which case the basename of FILE1 will be added.  The sessions
     SESS1 and SESS2 must be distinct.

     The operation is performed using pipes, so it is required that the
     connections still be valid in a subshell, which is not the case
     under versions of some operating systems, presumably due to a
     system bug.



25.3.8 Bookmarks
----------------

The two functions zfmark and zfgoto allow you to `bookmark' the present
location (host, user and directory) of the current FTP connection for
later use.  The file to be used for storing and retrieving bookmarks is
given by the parameter $ZFTP_BMFILE; if not set when one of the two
functions is called, it will be set to the file .zfbkmarks in the
directory where your zsh startup files live (usually ~).


zfmark [ BOOKMARK ]
     If given an argument, mark the current host, user and directory
     under the name BOOKMARK for later use by zfgoto.  If there is no
     connection open, use the values for the last connection
     immediately before it was closed; it is an error if there was
     none.  Any existing bookmark under the same name will be silently
     replaced.

     If not given an argument, list the existing bookmarks and the
     points to which they refer in the form USER@HOST:DIRECTORY; this
     is the format in which they are stored, and the file may be edited
     directly.

zfgoto [ -n ] BOOKMARK
     Return to the location given by BOOKMARK, as previously set by
     zfmark.  If the location has user `ftp' or `anonymous', open the
     connection with zfanon, so that no password is required.  If the
     user and host parameters match those stored for the current
     session, if any, those will be used, and again no password is
     required.  Otherwise a password will be prompted for.

     With the option -n, the bookmark is taken to be a nickname stored
     by the ncftp program in its bookmark file, which is assumed to be
     ~/.ncftp/bookmarks.  The function works identically in other ways.
     Note that there is no mechanism for adding or modifying ncftp
     bookmarks from the zftp functions.



25.3.9 Other functions
----------------------

Mostly, these functions will not be called directly (apart from
zfinit), but are described here for completeness.  You may wish to
alter zftp_chpwd and zftp_progress, in particular.


zfinit [ -n ]
     As described above, this is used to initialize the zftp function
     system.  The -n option should be used if the zftp command is
     already built into the shell.

zfautocheck [ -dn ]
     This function is called to implement automatic reopening
     behaviour, as described in more detail below.  The options must
     appear in the first argument; -n prevents the command from
     changing to the old directory, while -d prevents it from setting
     the variable do_close, which it otherwise does as a flag for
     automatically closing the connection after a transfer.  The host
     and directory for the last session are stored in the variable
     $zflastsession, but the internal host/user/password parameters
     must also be correctly set.

zfcd_match PREFIX SUFFIX
     This performs matching for completion of remote directory names.
     If the remote server is UNIX, it will attempt to persuade the
     server to list the remote directory with subdirectories marked,
     which usually works but is not guaranteed.  On other hosts it
     simply calls zfget_match and hence completes all files, not just
     directories.  On some systems, directories may not even look like
     filenames.

zfget_match PREFIX SUFFIX
     This performs matching for completion of remote filenames.  It
     caches files for the current directory (only) in the shell
     parameter $zftp_fcache.  It is in the form to be called by the -K
     option of compctl, but also works when called from a widget-style
     completion function with PREFIX and SUFFIX set appropriately.

zfrglob VARNAME
     Perform remote globbing, as describes in more detail below.
     VARNAME is the name of a variable containing the pattern to be
     expanded; if there were any matches, the same variable will be set
     to the expanded set of filenames on return.

zfrtime LFILE RFILE [ TIME ]
     Set the local file LFILE to have the same modification time as the
     remote file RFILE, or the explicit time TIME in FTP format
     CCYYMMDDhhmmSS for the GMT timezone.  This uses the shell's
     zsh/datetime module to perform the conversion from GMT to local
     time.

zftp_chpwd
     This function is called every time a connection is opened, or
     closed, or the remote directory changes.  This version alters the
     title bar of an xterm-compatible or sun-cmd terminal emulator to
     reflect the local and remote hostnames and current directories.
     It works best when combined with the function chpwd.  In
     particular, a function of the form


          chpwd() {
            if [[ -n $ZFTP_USER ]]; then
              zftp_chpwd
            else
              # usual chpwd e.g put host:directory in title bar
            fi
          }

     fits in well.

zftp_progress
     This function shows the status of the transfer.  It will not write
     anything unless the output is going to a terminal; however, if you
     transfer files in the background, you should turn off progress
     reports by hand using `zstyle ':zftp:*' progress none'.  Note also
     that if you alter it, any output _must_ be to standard error, as
     standard output may be a file being received.  The form of the
     progress meter, or whether it is used at all, can be configured
     without altering the function, as described in the next section.

zffcache
     This is used to implement caching of files in the current
     directory for each session separately.  It is used by zfget_match
     and zfrglob.



File: zsh.info,  Node: Miscellaneous Features,  Prev: Zftp Functions,  Up: Zftp Function System

25.4 Miscellaneous Features
===========================



25.4.1 Configuration
--------------------



Various styles are available using the standard shell style mechanism,
described in *note The zsh/zutil Module::. Briefly, the command `zstyle
':zftp:*' STYLE VALUE ...'.  defines the STYLE to have value VALUE;
more than one value may be given, although that is not useful in the
cases described here.  These values will then be used throughout the
zftp function system.  For more precise control, the first argument,
which gives a context in which the style applies, can be modified to
include a particular function, as for example `:zftp:zfget': the style
will then have the given value only in the zfget function.  Values for
the same style in different contexts may be set; the most specific
function will be used, where strings are held to be more specific than
patterns, and longer patterns and shorter patterns.  Note that only the
top level function name, as called by the user, is used; calling of
lower level functions is transparent to the user.  Hence modifications
to the title bar in zftp_chpwd use the contexts :zftp:zfopen,
:zftp:zfcd, etc., depending where it was called from.  The following
styles are understood:


progress
     Controls the way that zftp_progress reports on the progress of a
     transfer.  If empty, unset, or `none', no progress report is made;
     if `bar' a growing bar of inverse video is shown; if `percent' (or
     any other string, though this may change in future), the
     percentage of the file transferred is shown.  The bar meter
     requires that the width of the terminal be available via the
     $COLUMNS parameter (normally this is set automatically).  If the
     size of the file being transferred is not available, bar and
     percent meters will simply show the number of bytes transferred so
     far.

     When zfinit is run, if this style is not defined for the context
     :zftp:*, it will be set to `bar'.

update
     Specifies the minimum time interval between updates of the
     progress meter in seconds.  No update is made unless new data has
     been received, so the actual time interval is limited only by
     $ZFTP_TIMEOUT.

     As described for progress, zfinit will force this to default to 1.

remote-glob
     If set to `1', `yes' or `true', filename generation (globbing) is
     performed on the remote machine instead of by zsh itself; see
     below.

titlebar
     If set to `1', `yes' or `true', zftp_chpwd will put the remote
     host and remote directory into the titlebar of terminal emulators
     such as xterm or sun-cmd that allow this.

     As described for progress, zfinit will force this to default to 1.

chpwd
     If set to `1' `yes' or `true', zftp_chpwd will call the function
     chpwd when a connection is closed.  This is useful if the remote
     host details were put into the terminal title bar by zftp_chpwd
     and your usual chpwd also modifies the title bar.

     When zfinit is run, it will determine whether chpwd exists and if
     so it will set the default value for the style to 1 if none exists
     already.


Note that there is also an associative array zfconfig which contains
values used by the function system.  This should not be modified or
overwritten.



25.4.2 Remote globbing
----------------------



The commands for retrieving files usually perform filename generation
(globbing) on their arguments; this can be turned off by passing the
option -G to each of the commands.  Normally this operates by
retrieving a complete list of files for the directory in question, then
matching these locally against the pattern supplied.  This has the
advantage that the full range of zsh patterns (respecting the setting
of the option EXTENDED_GLOB) can be used.  However, it means that the
directory part of a filename will not be expanded and must be given
exactly.  If the remote server does not support the UNIX directory
semantics, directory handling is problematic and it is recommended that
globbing only be used within the current directory.  The list of files
in the current directory, if retrieved, will be cached, so that
subsequent globs in the same directory without an intervening zfcd are
much faster.

If the remote-glob style (see above) is set, globbing is instead
performed on the remote host: the server is asked for a list of matching
files.  This is highly dependent on how the server is implemented,
though typically UNIX servers will provide support for basic glob
patterns.  This may in some cases be faster, as it avoids retrieving
the entire list of directory contents.



25.4.3 Automatic and temporary reopening
----------------------------------------



As described for the zfopen command, a subsequent zfopen with no
parameters will reopen the connection to the last host (this includes
connections made with the zfanon command).  Opened in this fashion, the
connection starts in the default remote directory and will remain open
until explicitly closed.

Automatic re-opening is also available.  If a connection is not
currently open and a command requiring a connection is given, the last
connection is implicitly reopened.  In this case the directory which
was current when the connection was closed again becomes the current
directory (unless, of course, the command given changes it).  Automatic
reopening will also take place if the connection was close by the
remote server for whatever reason (e.g. a timeout).  It is not
available if the -1 option to zfopen or zfanon was used.

Furthermore, if the command issued is a file transfer, the connection
will be closed after the transfer is finished, hence providing a
one-shot mode for transfers.  This does not apply to directory changing
or listing commands; for example a zfdir may reopen a connection but
will leave it open.  Also, automatic closure will only ever happen in
the same command as automatic opening, i.e a zfdir directly followed by
a