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SCREEN(1)                                                            SCREEN(1)



NAME
       screen - screen manager with VT100/ANSI terminal emulation



SYNOPSIS
       screen [ -options ] [ cmd [ args ] ]
       screen -r [[pid.]tty[.host]]
       screen -r sessionowner/[[pid.]tty[.host]]



DESCRIPTION
       Screen  is  a  full-screen window manager that multiplexes a physical terminal between several processes (typi-
       cally interactive shells).  Each virtual terminal provides the functions of a DEC VT100 terminal and, in  addi-
       tion,  several  control  functions  from  the  ISO  6429  (ECMA  48,  ANSI  X3.64) and ISO 2022 standards (e.g.
       insert/delete line and support for multiple character sets).  There is a scrollback  history  buffer  for  each
       virtual terminal and a copy-and-paste mechanism that allows moving text regions between windows.

       When  screen  is called, it creates a single window with a shell in it (or the specified command) and then gets
       out of your way so that you can use the program as you normally would.  Then, at any time, you can  create  new
       (full-screen)  windows  with other programs in them (including more shells), kill existing windows, view a list
       of windows, turn output logging on and off, copy-and-paste text between windows, view the  scrollback  history,
       switch  between windows in whatever manner you wish, etc. All windows run their programs completely independent
       of each other. Programs continue to run when their window is currently not visible  and  even  when  the  whole
       screen session is detached from the user's terminal.  When a program terminates, screen (per default) kills the
       window that contained it.  If this window was in the foreground, the display switches to the  previous  window;
       if none are left, screen exits.

       Everything  you  type  is sent to the program running in the current window.  The only exception to this is the
       one keystroke that is used to initiate a command to the window manager.  By default, each command begins with a
       control-a (abbreviated C-a from now on), and is followed by one other keystroke.  The command character and all
       the key bindings can be fully customized to be anything you like, though they  are  always  two  characters  in
       length.

       Screen does not understand the prefix "C-" to mean control.  Please use the caret notation ("^A" instead of "C-
       a") as arguments to e.g. the escape command or the -e option.  Screen will also print out control characters in
       caret notation.

       The  standard  way  to  create  a new window is to type "C-a c".  This creates a new window running a shell and
       switches to that window immediately, regardless of the state of the process  running  in  the  current  window.
       Similarly,  you can create a new window with a custom command in it by first binding the command to a keystroke
       (in your .screenrc file or at the "C-a :" command line) and then using it just like the "C-a  c"  command.   In
       addition, new windows can be created by running a command like:

              screen emacs prog.c

       from  a  shell  prompt  within a previously created window.  This will not run another copy of screen, but will
       instead supply the command name and its arguments to the window manager  (specified  in  the  $STY  environment
       variable)  who  will  use it to create the new window.  The above example would start the emacs editor (editing
       prog.c) and switch to its window.

       If "/etc/utmp" is writable by screen, an appropriate record will be written to this file for each  window,  and
       removed  when the window is terminated.  This is useful for working with "talk", "script", "shutdown", "rsend",
       "sccs" and other similar programs that use the utmp file to determine who you are. As long as screen is  active
       on your terminal, the terminal's own record is removed from the utmp file. See also "C-a L".



GETTING STARTED
       Before you begin to use screen you'll need to make sure you have correctly selected your terminal type, just as
       you would for any other termcap/terminfo program.  (You can do this by using tset for example.)

       If you're impatient and want to get started without doing a lot more reading, you should remember this one com-
       mand:   "C-a  ?".   Typing  these two characters will display a list of the available screen commands and their
       bindings. Each keystroke is discussed in the section "DEFAULT KEY BINDINGS". The manual section "CUSTOMIZATION"
       deals with the contents of your .screenrc.

       If  your  terminal  is  a  "true"  auto-margin terminal (it doesn't allow the last position on the screen to be
       updated without scrolling the screen) consider using a version of your terminal's termcap  that  has  automatic
       margins  turned  off.  This will ensure an accurate and optimal update of the screen in all circumstances. Most
       terminals nowadays have "magic" margins (automatic margins plus usable last column). This is  the  VT100  style
       type  and  perfectly suited for screen.  If all you've got is a "true" auto-margin terminal screen will be con-
       tent to use it, but updating a character put into the last position on the screen may not be possible until the
       screen scrolls or the character is moved into a safe position in some other way. This delay can be shortened by
       using a terminal with insert-character capability.



COMMAND-LINE OPTIONS
       Screen has the following command-line options:

       -a   include all capabilities (with some minor exceptions) in each window's termcap, even if screen must redraw
            parts of the display in order to implement a function.

       -A   Adapt  the  sizes of all windows to the size of the current terminal.  By default, screen tries to restore
            its old window sizes when attaching to resizable terminals (those  with  "WS"  in  its  description,  e.g.
            suncmd or some xterm).

       -c file
            override the default configuration file from "$HOME/.screenrc" to file.

       -d|-D [pid.tty.host]
            does not start screen, but detaches the elsewhere running screen session. It has the same effect as typing
            "C-a d" from screen's controlling terminal. -D is the equivalent to the power detach key.  If  no  session
            can be detached, this option is ignored. In combination with the -r/-R option more powerful effects can be
            achieved:

       -d -r   Reattach a session and if necessary detach it first.

       -d -R   Reattach a session and if necessary detach or even create it first.

       -d -RR  Reattach a session and if necessary detach or create it. Use the first session if more than one session
               is available.

       -D -r   Reattach a session. If necessary detach and logout remotely first.

       -D -R   Attach  here and now. In detail this means: If a session is running, then reattach. If necessary detach
               and logout remotely first.  If it was not running create it and notify the user. This is  the  author's
               favorite.

       -D -RR  Attach here and now. Whatever that means, just do it.

            Note: It is always a good idea to check the status of your sessions by means of "screen -list".

       -e xy
            specifies  the  command  character  to  be x and the character generating a literal command character to y
            (when typed after the command character).  The default is  "C-a"  and  'a',  which  can  be  specified  as
            "-e^Aa".   When  creating a screen session, this option sets the default command character. In a multiuser
            session all users added will start off with this command character. But when attaching to an already  run-
            ning session, this option changes only the command character of the attaching user.  This option is equiv-
            alent to either the commands "defescape" or "escape" respectively.

       -f, -fn, and -fa
            turns flow-control on, off, or "automatic switching mode".  This can also be defined through the "defflow"
            .screenrc command.

       -h num
            Specifies the history scrollback buffer to be num lines high.

       -i   will  cause  the interrupt key (usually C-c) to interrupt the display immediately when flow-control is on.
            See the "defflow" .screenrc command for details.  The use of this option is discouraged.

       -l and -ln
            turns login mode on or off (for /etc/utmp updating).  This can also  be  defined  through  the  "deflogin"
            .screenrc command.

       -ls and -list
            does  not  start screen, but prints a list of pid.tty.host strings identifying your screen sessions.  Ses-
            sions marked 'detached' can be resumed with "screen -r". Those marked 'attached' are running  and  have  a
            controlling  terminal.  If  the  session  runs in multiuser mode, it is marked 'multi'. Sessions marked as
            'unreachable' either live on a different host or are 'dead'.  An unreachable session is  considered  dead,
            when  its  name matches either the name of the local host, or the specified parameter, if any.  See the -r
            flag for a description how to construct matches.  Sessions marked as 'dead' should be  thoroughly  checked
            and removed.  Ask your system administrator if you are not sure. Remove sessions with the -wipe option.

       -L   tells screen to turn on automatic output logging for the windows.

       -m   causes  screen  to  ignore  the  $STY  environment variable. With "screen -m" creation of a new session is
            enforced, regardless whether screen is called from within another screen session or not. This flag  has  a
            special meaning in connection with the '-d' option:

       -d -m   Start  screen  in  "detached" mode. This creates a new session but doesn't attach to it. This is useful
               for system startup scripts.

       -D -m   This also starts screen in "detached" mode, but doesn't fork a new process. The command  exits  if  the
               session terminates.

       -O   selects  a more optimal output mode for your terminal rather than true VT100 emulation (only affects auto-
            margin terminals without 'LP').  This can also be set in your .screenrc by specifying 'OP' in a  "termcap"
            command.

       -p number_or_name
            Preselect  a  window. This is usefull when you want to reattach to a specific windor or you want to send a
            command via the "-X" option to a specific window. As with screen's select commant, "-" selects  the  blank
            window. As a special case for reattach, "=" brings up the windowlist on the blank window.

       -q   Suppress printing of error messages. In combination with "-ls" the exit value is as follows: 9 indicates a
            directory without sessions. 10 indicates a directory with running but  not  attachable  sessions.  11  (or
            more)  indicates  1  (or more) usable sessions.  In combination with "-r" the exit value is as follows: 10
            indicates that there is no session to resume. 12 (or more) indicates that there are 2 (or  more)  sessions
            to resume and you should specify which one to choose.  In all other cases "-q" has no effect.

       -r [pid.tty.host]
       -r sessionowner/[pid.tty.host]
            resumes  a  detached  screen session.  No other options (except combinations with -d/-D) may be specified,
            though an optional prefix of [pid.]tty.host may be needed to distinguish between multiple detached  screen
            sessions.   The  second  form  is used to connect to another user's screen session which runs in multiuser
            mode. This indicates that screen should look for sessions  in  another  user's  directory.  This  requires
            setuid-root.

       -R   attempts  to  resume  the  first  detached screen session it finds.  If successful, all other command-line
            options are ignored.  If no detached session exists, starts a new session  using  the  specified  options,
            just  as  if  -R  had  not  been specified. The option is set by default if screen is run as a login-shell
            (actually screen uses "-xRR" in that case).  For combinations with the -d/-D option see there.

       -s   sets the default shell to the program specified, instead of the value in the environment  variable  $SHELL
            (or "/bin/sh" if not defined).  This can also be defined through the "shell" .screenrc command.

       -S sessionname
            When  creating  a  new session, this option can be used to specify a meaningful name for the session. This
            name identifies the session for "screen -list"  and  "screen  -r"  actions.  It  substitutes  the  default
            [tty.host] suffix.

       -t name
            sets  the  title (a.k.a.) for the default shell or specified program.  See also the "shelltitle" .screenrc
            command.

       -U   Run screen in UTF-8 mode. This option tells screen that your terminal sends and understands UTF-8  encoded
            characters. It also sets the default encoding for new windows to 'utf8'.

       -v   Print version number.

       -wipe [match]
            does  the  same  as  "screen  -ls",  but removes destroyed sessions instead of marking them as 'dead'.  An
            unreachable session is considered dead, when its name matches either the name of the local  host,  or  the
            explicitly given parameter, if any.  See the -r flag for a description how to construct matches.

       -x   Attach to a not detached screen session. (Multi display mode).

       -X   Send  the specified command to a running screen session. You can use the -d or -r option to tell screen to
            look only for attached or detached screen sessions. Note that this command doesn't work if the session  is
            password protected.



DEFAULT KEY BINDINGS
       As  mentioned,  each screen command consists of a "C-a" followed by one other character.  For your convenience,
       all commands that are bound to lower-case letters are also bound to their control character counterparts  (with
       the  exception  of  "C-a a"; see below), thus, "C-a c" as well as "C-a C-c" can be used to create a window. See
       section "CUSTOMIZATION" for a description of the command.


       The following table shows the default key bindings:

       C-a '       (select)      Prompt for a window name or number to switch to.

       C-a "       (windowlist -b)
                                 Present a list of all windows for selection.

       C-a 0       (select 0)
        ...           ...
       C-a 9       (select 9)
       C-a -       (select -)    Switch to window number 0 - 9, or to the blank window.

       C-a tab     (focus)       Switch the input focus to the next region.

       C-a C-a     (other)       Toggle to the window displayed previously.  Note that this binding  defaults  to  the
                                 command  character  typed  twice,  unless  overridden.   For instance, if you use the
                                 option "-e]x", this command becomes "]]".

       C-a a       (meta)        Send the command character (C-a) to window. See escape command.

       C-a A       (title)       Allow the user to enter a name for the current window.

       C-a b
       C-a C-b     (break)       Send a break to window.

       C-a B       (pow_break)   Reopen the terminal line and send a break.

       C-a c
       C-a C-c     (screen)      Create a new window with a shell and switch to that window.

       C-a C       (clear)       Clear the screen.

       C-a d
       C-a C-d     (detach)      Detach screen from this terminal.

       C-a D D     (pow_detach)  Detach and logout.

       C-a f
       C-a C-f     (flow)        Toggle flow on, off or auto.

       C-a F       (fit)         Resize the window to the current region size.

       C-a C-g     (vbell)       Toggles screen's visual bell mode.

       C-a h       (hardcopy)    Write a hardcopy of the current window to the file "hardcopy.n".

       C-a H       (log)         Begins/ends logging of the current window to the file "screenlog.n".

       C-a i
       C-a C-i     (info)        Show info about this window.

       C-a k
       C-a C-k     (kill)        Destroy current window.

       C-a l
       C-a C-l     (redisplay)   Fully refresh current window.

       C-a L       (login)       Toggle this windows login slot. Available only if screen is configured to update  the
                                 utmp database.

       C-a m
       C-a C-m     (lastmsg)     Repeat the last message displayed in the message line.

       C-a M       (monitor)     Toggles monitoring of the current window.

       C-a space
       C-a n
       C-a C-n     (next)        Switch to the next window.

       C-a N       (number)      Show the number (and title) of the current window.

       C-a backspace
       C-a h
       C-a p
       C-a C-p     (prev)        Switch to the previous window (opposite of C-a n).

       C-a q
       C-a C-q     (xon)         Send a control-q to the current window.

       C-a Q       (only)        Delete all regions but the current one.

       C-a r
       C-a C-r     (wrap)        Toggle  the  current  window's line-wrap setting (turn the current window's automatic
                                 margins on and off).

       C-a s
       C-a C-s     (xoff)        Send a control-s to the current window.

       C-a S       (split)       Split the current region into two new ones.

       C-a t
       C-a C-t     (time)        Show system information.

       C-a v       (version)     Display the version and compilation date.

       C-a C-v     (digraph)     Enter digraph.

       C-a w
       C-a C-w     (windows)     Show a list of window.

       C-a W       (width)       Toggle 80/132 columns.

       C-a x
       C-a C-x     (lockscreen)  Lock this terminal.

       C-a X       (remove)      Kill the current region.

       C-a z
       C-a C-z     (suspend)     Suspend screen.  Your system must support BSD-style job-control.

       C-a Z       (reset)       Reset the virtual terminal to its "power-on" values.

       C-a .       (dumptermcap) Write out a ".termcap" file.

       C-a ?       (help)        Show key bindings.

       C-a C-\     (quit)        Kill all windows and terminate screen.

       C-a :       (colon)       Enter command line mode.

       C-a [
       C-a C-[
       C-a esc     (copy)        Enter copy/scrollback mode.

       C-a ]       (paste .)     Write the contents of the paste buffer to the stdin queue of the current window.

       C-a {
       C-a }       (history)     Copy and paste a previous (command) line.

       C-a >       (writebuf)    Write paste buffer to a file.

       C-a <       (readbuf)     Reads the screen-exchange file into the paste buffer.

       C-a =       (removebuf)   Removes the file used by C-a < and C-a >.

       C-a ,       (license)     Shows where screen comes from, where it went to and why you can use it.

       C-a _       (silence)     Start/stop monitoring the current window for inactivity.

       C-a *       (displays)    Show a listing of all currently attached displays.



CUSTOMIZATION
       The  "socket  directory"  defaults  either  to  $HOME/.screen  or  simply  to  /tmp/screens  or  preferably  to
       /usr/local/screens  chosen  at  compile-time. If screen is installed setuid-root, then the administrator should
       compile screen with an adequate (not NFS mounted) socket directory. If screen is not running  setuid-root,  the
       user can specify any mode 700 directory in the environment variable $SCREENDIR.

       When  screen  is invoked, it executes initialization commands from the files "/etc/screenrc" and ".screenrc" in
       the user's home directory. These are the "programmer's defaults" that can be overridden in the following  ways:
       for  the  global screenrc file screen searches for the environment variable $SYSSCREENRC (this override feature
       may  be  disabled  at  compile-time).  The  user  specific  screenrc  file  is  searched  in  $SCREENRC,   then
       $HOME/.screenrc.  The command line option -c takes precedence over the above user screenrc files.

       Commands  in these files are used to set options, bind functions to keys, and to automatically establish one or
       more windows at the beginning of your screen session.  Commands are listed one per line, with empty lines being
       ignored.   A  command's  arguments  are  separated by tabs or spaces, and may be surrounded by single or double
       quotes.  A '#' turns the rest of the line into a comment, except in quotes.  Unintelligible  lines  are  warned
       about  and  ignored.   Commands  may  contain references to environment variables. The syntax is the shell-like
       "$VAR " or "${VAR}". Note that this causes incompatibility with previous screen versions, as now the  '$'-char-
       acter has to be protected with '\' if no variable substitution shall be performed. A string in single-quotes is
       also protected from variable substitution.

       Two configuration files are shipped as examples with your screen  distribution:  "etc/screenrc"  and  "etc/etc-
       screenrc". They contain a number of useful examples for various commands.

       Customization  can  also be done 'on-line'. To enter the command mode type 'C-a :'. Note that commands starting
       with "def" change default values, while others change current settings.

       The following commands are available:

       acladd usernames [crypted-pw]
       addacl usernames

       Enable users to fully access this screen session. Usernames can be one user or a comma separated list of users.
       This  command  enables  to  attach  to the screen session and performs the equivalent of 'aclchg usernames +rwx
       "#?"'.  executed. To add a user with restricted access, use the 'aclchg' command below.  If an optional  second
       parameter  is  supplied,  it  should  be  a  crypted  password  for the named user(s). 'Addacl' is a synonym to
       'acladd'.  Multi user mode only.

       aclchg usernames permbits list
       chacl usernames permbits list

       Change permissions for a comma separated list of users. Permission bits are represented as 'r',  'w'  and  'x'.
       Prefixing  '+' grants the permission, '-' removes it. The third parameter is a comma separated list of commands
       and/or windows (specified either by number or title). The special list '#' refers to all windows,  '?'  to  all
       commands.  if usernames consists of a single '*', all known users are affected.  A command can be executed when
       the user has the 'x' bit for it.  The user can type input to a window when he has its 'w' bit set and no  other
       user  obtains  a  writelock for this window.  Other bits are currently ignored.  To withdraw the writelock from
       another user in window 2: 'aclchg username -w+w 2'.  To allow read-only access to the session: 'aclchg username
       -w  "#"'.  As  soon as a user's name is known to screen he can attach to the session and (per default) has full
       permissions for all command and windows. Execution permission for the acl commands, 'at' and others should also
       be removed or the user may be able to regain write permission.  Rights of the special username nobody cannot be
       changed (see the "su" command).  'Chacl' is a synonym to 'aclchg'.  Multi user mode only.

       acldel username

       Remove a user from screen's access control list. If currently attached, all the user's  displays  are  detached
       from the session. He cannot attach again.  Multi user mode only.

       aclgrp username [groupname]

       Creates  groups  of  users  that share common access rights. The name of the group is the username of the group
       leader. Each member of the group inherits the permissions that are granted to the group leader. That means,  if
       a  user  fails  an access check, another check is made for the group leader.  A user is removed from all groups
       the special value "none" is used for groupname.  If the second parameter is omitted all groups the user  is  in
       are listed.

       aclumask [[users]+bits |[users]-bits .... ]
       umask [[users]+bits |[users]-bits .... ]

       This specifies the access other users have to windows that will be created by the caller of the command.  Users
       may be no, one or a comma separated list of known usernames. If no users are specified, a list of all currently
       known  users is assumed.  Bits is any combination of access control bits allowed defined with the "aclchg" com-
       mand. The special username "?" predefines the access that not yet known users will be  granted  to  any  window
       initially.   The  special  username "??" predefines the access that not yet known users are granted to any com-
       mand.  Rights of the special username nobody cannot be changed (see the "su" command).  'Umask' is a synonym to
       'aclumask'.

       activity message

       When  any activity occurs in a background window that is being monitored, screen displays a notification in the
       message line.  The notification message can be re-defined by means of the "activity" command.  Each  occurrence
       of  '%'  in message is replaced by the number of the window in which activity has occurred, and each occurrence
       of '^G' is replaced by the definition for bell in your termcap (usually an audible bell).  The default  message
       is

                   'Activity in window %n'

       Note that monitoring is off for all windows by default, but can be altered by use of the "monitor" command (C-a
       M).

       allpartial on|off

       If set to on, only the current cursor line is refreshed on window change.  This affects all windows and is use-
       ful  for  slow  terminal  lines.  The previous setting of full/partial refresh for each window is restored with
       "allpartial off".  This is a global flag that immediately takes effect on all windows overriding the  "partial"
       settings. It does not change the default redraw behavior of newly created windows.

       altscreen on|off

       If  set to on, "alternate screen" support is enabled in virtual terminals, just like in xterm.  Initial setting
       is 'off'.

       at [identifier][#|*|%] command [args ... ]

       Execute a command at other displays or windows as if it had been entered there.  "At" changes the context  (the
       'current  window'  or  'current display' setting) of the command. If the first parameter describes a non-unique
       context, the command will be executed multiple times. If the first parameter is of the form 'identifier*'  then
       identifier  is  matched  against  user  names.   The  command is executed once for each display of the selected
       user(s). If the first parameter is of the form 'identifier%' identifier is matched against  displays.  Displays
       are  named after the ttys they attach. The prefix '/dev/' or '/dev/tty' may be omitted from the identifier.  If
       identifier has a '#' or nothing appended  it  is  matched  against  window  numbers  and  titles.  Omitting  an
       identifier  in  front of the '#', '*' or '%'-character selects all users, displays or windows because a prefix-
       match is performed. Note that on the affected display(s) a short message will describe what  happened.  Permis-
       sion  is  checked  for initiator of the "at" command, not for the owners of the affected display(s).  Note that
       the '#' character works as a comment introducer when it is preceded by whitespace. This can be escaped by  pre-
       fixing  a '\'.  Permission is checked for the initiator of the "at" command, not for the owners of the affected
       display(s).
       Caveat: When matching against windows, the command is executed at least once per window. Commands  that  change
       the  internal  arrangement of windows (like "other") may be called again. In shared windows the command will be
       repeated for each attached display. Beware, when issuing toggle commands like  "login"!   Some  commands  (e.g.
       "process") require that a display is associated with the target windows.  These commands may not work correctly
       under "at" looping over windows.

       attrcolor attrib [attribute/color-modifier]

       This command can be used to highlight attributes by changing the color of the text. If the attribute attrib  is
       in  use,  the  specified  attribute/color modifier is also applied. If no modifier is given, the current one is
       deleted. See the "STRING ESCAPES" chapter for the syntax  of  the  modifier.  Screen  understands  two  pseudo-
       attributes, "i" stands for high-intensity foreground color and "I" for high-intensity background color.

       Examples:

              attrcolor b "R"

       Change the color to bright red if bold text is to be printed.

              attrcolor u "-u b"

       Use blue text instead of underline.

              attrcolor b ".I"

       Use bright colors for bold text. Most terminal emulators do this already.

              attrcolor i "+b"

       Make bright colored text also bold.

       autodetach on|off

       Sets whether screen will automatically detach upon hangup, which saves all your running programs until they are
       resumed with a screen -r command.  When turned off, a hangup signal will terminate screen and all the processes
       it contains. Autodetach is on by default.

       autonuke on|off

       Sets  whether a clear screen sequence should nuke all the output that has not been written to the terminal. See
       also "obuflimit".

       backtick id lifespan autorefresh cmd args...
       backtick id

       Program the backtick command with the numerical id id.  The output of such a command is used  for  substitution
       of  the  "%'"  string  escape.  The specified lifespan is the number of seconds the output is considered valid.
       After this time, the command is run again if a corresponding string escape  is  encountered.   The  autorefresh
       parameter  triggers  an automatic refresh for caption and hardstatus strings after the specified number of sec-
       onds. Only the last line of output is used for substitution.
       If both the lifespan and the autorefresh parameters are zero, the backtick program is expected to stay  in  the
       background  and  generate  output once in a while.  In this case, the command is executed right away and screen
       stores the last line of output. If a new line gets printed screen will automatically refresh the hardstatus  or
       the captions.
       The second form of the command deletes the backtick command with the numerical id id.

       bce [on|off]

       Change   background-color-erase   setting.   If   "bce"   is   set   to   on,  all  characters  cleared  by  an
       erase/insert/scroll/clear operation will be displayed in the current background color.  Otherwise  the  default
       background color is used.

       bell_msg [message]

       When  a bell character is sent to a background window, screen displays a notification in the message line.  The
       notification message can be re-defined by this command.  Each occurrence of '%' in message is replaced  by  the
       number  of  the window to which a bell has been sent, and each occurrence of '^G' is replaced by the definition
       for bell in your termcap (usually an audible bell).  The default message is

                   'Bell in window %n'

       An empty message can be supplied to the "bell_msg" command to suppress output of a message line (bell_msg  "").
       Without parameter, the current message is shown.

       bind [-c class] key [command [args]]

       Bind  a command to a key.  By default, most of the commands provided by screen are bound to one or more keys as
       indicated in the "DEFAULT KEY BINDINGS" section, e.g. the command to create a new window is bound to "C-c"  and
       "c".  The "bind" command can be used to redefine the key bindings and to define new bindings.  The key argument
       is either a single character, a two-character sequence of the form "^x" (meaning "C-x"), a  backslash  followed
       by an octal number (specifying the ASCII code of the character), or a backslash followed by a second character,
       such as "\^" or "\\".  The argument can also be quoted, if you like.  If no further argument is given, any pre-
       viously  established  binding  for this key is removed.  The command argument can be any command listed in this
       section.

       If a command class is specified via the "-c" option, the key is bound for the specified class.  Use  the  "com-
       mand" command to activate a class. Command classes can be used to create multiple command keys or multi-charac-
       ter bindings.

       Some examples:

                   bind ' ' windows
                   bind ^k
                   bind k
                   bind K kill
                   bind ^f screen telnet foobar
                   bind \033 screen -ln -t root -h 1000 9 su

       would bind the space key to the command that displays a list of windows (so that the command usually invoked by
       "C-a  C-w"  would  also be available as "C-a space"). The next three lines remove the default kill binding from
       "C-a C-k" and "C-a k".  "C-a K" is then bound to the kill command. Then it binds "C-f" to the command "create a
       window  with  a TELNET connection to foobar", and bind "escape" to the command that creates an non-login window
       with a.k.a. "root" in slot #9, with a superuser shell and a scrollback buffer of 1000 lines.

                   bind -c demo1 0 select 10
                   bind -c demo1 1 select 11
                   bind -c demo1 2 select 12
                   bindkey "^B" command -c demo1

       makes "C-b 0" select window 10, "C-b 1" window 11, etc.

                   bind -c demo2 0 select 10
                   bind -c demo2 1 select 11
                   bind -c demo2 2 select 12
                   bind - command -c demo2

       makes "C-a - 0" select window 10, "C-a - 1" window 11, etc.

       bindkey [-d] [-m] [-a] [[-k|-t] string [cmd args]]

       This command manages screen's input translation tables. Every entry in one of the tables tells  screen  how  to
       react  if  a  certain  sequence  of  characters is encountered. There are three tables: one that should contain
       actions programmed by the user, one for the default actions used for terminal emulation and  one  for  screen's
       copy mode to do cursor movement. See section "INPUT TRANSLATION" for a list of default key bindings.
       If  the -d option is given, bindkey modifies the default table, -m changes the copy mode table and with neither
       option the user table is selected.  The argument string is the sequence of characters to  which  an  action  is
       bound. This can either be a fixed string or a termcap keyboard capability name (selectable with the -k option).
       Some keys on a VT100 terminal can send a different string if application mode is  turned  on  (e.g  the  cursor
       keys).  Such keys have two entries in the translation table. You can select the application mode entry by spec-
       ifying the -a option.
       The -t option tells screen not to do inter-character timing. One cannot turn off the timing if a termcap  capa-
       bility is used.
       Cmd  can  be  any  of screen's commands with an arbitrary number of args.  If cmd is omitted the key-binding is
       removed from the table.
       Here are some examples of keyboard bindings:

               bindkey -d
       Show all of the default key bindings. The application mode entries are marked with [A].

               bindkey -k k1 select 1
       Make the "F1" key switch to window one.

               bindkey -t foo stuff barfoo
       Make "foo" an abbreviation of the word "barfoo". Timeout is disabled so that users can type slowly.

               bindkey "\024" mapdefault
       This key-binding makes "^T" an escape character for key-bindings. If you did the above "stuff barfoo"  binding,
       you  can  enter  the word "foo" by typing "^Tfoo". If you want to insert a "^T" you have to press the key twice
       (i.e. escape the escape binding).

               bindkey -k F1 command
       Make the F11 (not F1!) key an alternative screen escape (besides ^A).

       break [duration]

       Send a break signal for duration*0.25 seconds to this window.  For non-Posix systems the time interval  may  be
       rounded  up  to  full seconds.  Most useful if a character device is attached to the window rather than a shell
       process (See also chapter "WINDOW TYPES"). The maximum duration of a break signal is limited to 15 seconds.

       blanker

       Activate the screen blanker. First the screen is cleared. If no blanker  program  is  defined,  the  cursor  is
       turned  off, otherwise, the program is started and it's output is written to the screen.  The screen blanker is
       killed with the first keypress, the read key is discarded.
       This command is normally used together with the "idle" command.

       blankerprg [program args]

       Defines a blanker program. Disables the blanker program if no arguments are given.

       breaktype [tcsendbreak|TIOCSBRK |TCSBRK]

       Choose one of the available methods of generating a break signal for  terminal  devices.  This  command  should
       affect  the current window only.  But it still behaves identical to "defbreaktype". This will be changed in the
       future.  Calling "breaktype" with no parameter displays the break method for the current window.

       bufferfile [exchange-file]

       Change the filename used for reading and writing with the paste  buffer.   If  the  optional  argument  to  the
       "bufferfile"  command  is  omitted, the default setting ("/tmp/screen-exchange") is reactivated.  The following
       example will paste the system's password file into the screen window (using the  paste  buffer,  where  a  copy
       remains):

                   C-a : bufferfile /etc/passwd
                   C-a < C-a ]
                   C-a : bufferfile

       c1 [on|off]

       Change  c1  code  processing. "C1 on" tells screen to treat the input characters between 128 and 159 as control
       functions.  Such an 8-bit code is normally the same as ESC  followed  by  the  corresponding  7-bit  code.  The
       default setting is to process c1 codes and can be changed with the "defc1" command.  Users with fonts that have
       usable characters in the c1 positions may want to turn this off.

       caption always|splitonly [string]
       caption string [string]

       This command controls the display of the window captions. Normally a caption is only used if more than one win-
       dow  is  shown on the display (split screen mode). But if the type is set to always screen shows a caption even
       if only one window is displayed. The default is splitonly.

       The second form changes the text used for the caption. You can use all escapes from the "STRING ESCAPES"  chap-
       ter. Screen uses a default of '%3n %t'.

       You can mix both forms by providing a string as an additional argument.

       charset set

       Change  the  current  character  set slot designation and charset mapping.  The first four character of set are
       treated as charset designators while the fifth and sixth character must be in range '0'  to  '3'  and  set  the
       GL/GR  charset  mapping. On every position a '.' may be used to indicate that the corresponding charset/mapping
       should not be changed (set is padded to six characters internally by appending '.'  chars).  New  windows  have
       "BBBB02" as default charset, unless a "encoding" command is active.
       The current setting can be viewed with the "info" command.

       chdir [directory]

       Change  the  current  directory of screen to the specified directory or, if called without an argument, to your
       home directory (the value of the environment variable $HOME).  All windows that are created  by  means  of  the
       "screen" command from within ".screenrc" or by means of "C-a : screen ..." or "C-a c" use this as their default
       directory.  Without a chdir command, this would be the directory from which screen was invoked.   Hardcopy  and
       log  files  are always written to the window's default directory, not the current directory of the process run-
       ning in the window.  You can use this command multiple times in your .screenrc to start various windows in dif-
       ferent default directories, but the last chdir value will affect all the windows you create interactively.

       clear

       Clears the current window and saves its image to the scrollback buffer.

       colon [prefix]

       Allows  you  to  enter  ".screenrc" command lines. Useful for on-the-fly modification of key bindings, specific
       window creation and changing settings. Note that the "set" keyword no longer exists!  Usually  commands  affect
       the current window rather than default settings for future windows. Change defaults with commands starting with
       'def...'.

       If you consider this as the 'Ex command mode' of screen, you may regard "C-a esc" (copy mode) as its  'Vi  com-
       mand mode'.

       command [-c class]

       This command has the same effect as typing the screen escape character (^A). It is probably only useful for key
       bindings.  If the "-c" option is given, select the specified command class.  See also "bind" and "bindkey".

       compacthist [on|off]

       This tells screen whether to suppress trailing blank lines when scrolling up text into the history buffer.

       console [on|off]

       Grabs or un-grabs the machines console output to a window.  Note: Only the owner of /dev/console can  grab  the
       console output.  This command is only available if the machine supports the ioctl TIOCCONS.

       copy

       Enter copy/scrollback mode. This allows you to copy text from the current window and its history into the paste
       buffer. In this mode a vi-like 'full screen editor' is active:
       Movement keys:
         h, j, k, l move the cursor line by line or column by column.
         0, ^ and $ move to the leftmost column, to the first or last non-whitespace character on the line.
         H, M and L move the cursor to the leftmost column of the top, center or bottom line of the window.
         + and - positions one line up and down.
         G moves to the specified absolute line (default: end of buffer).
         | moves to the specified absolute column.
         w, b, e move the cursor word by word.
         B, E move the cursor WORD by WORD (as in vi).
         C-u and C-d scroll the display up/down by the specified amount of lines while preserving the cursor position.
           (Default: half screen-full).
         C-b and C-f scroll the display up/down a full screen.
         g moves to the beginning of the buffer.
         % jumps to the specified percentage of the buffer.

       Note:
           Emacs style movement keys can be customized by a .screenrc command.  (E.g. markkeys "h=^B:l=^F:$=^E") There
           is no simple method for a full emacs-style keymap, as this involves multi-character codes.

       Marking:
           The copy range is specified by setting two marks. The text between these marks will be highlighted. Press
         space to set the first or second mark respectively.
         Y and y used to mark one whole line or to mark from start of line.
         W marks exactly one word.
       Repeat count:
           Any of these commands can be prefixed with a repeat count number by pressing digits
         0..9 which is taken as a repeat count.
           Example: "C-a C-[ H 10 j 5 Y" will copy lines 11 to 15 into the paste buffer.
       Searching:
         / Vi-like search forward.
         ? Vi-like search backward.
         C-a s Emacs style incremental search forward.
         C-r Emacs style reverse i-search.
       Specials:
           There are however some keys that act differently than in vi.  Vi does not allow  one  to  yank  rectangular
           blocks of text, but screen does. Press
         c or C to set the left or right margin respectively. If no repeat count is given, both default to the current
           cursor position.
           Example: Try this on a rather full text screen: "C-a [ M 20 l SPACE c 10 l 5 j C SPACE".

           This moves one to the middle line of the screen, moves in 20 columns left, marks the beginning of the paste
           buffer,  sets  the  left column, moves 5 columns down, sets the right column, and then marks the end of the
           paste buffer. Now try:
           "C-a [ M 20 l SPACE 10 l 5 j SPACE"

           and notice the difference in the amount of text copied.
         J joins lines. It toggles between 4 modes: lines separated by a newline character (012),  lines  glued  seam-
           less,  lines separated by a single whitespace and comma separated lines. Note that you can prepend the new-
           line character with a carriage return character, by issuing a "crlf on".
         v is for all the vi users with ":set numbers" - it toggles the left margin between column 9 and 1. Press
         a before the final space key to toggle in append mode. Thus the contents of the  paste  buffer  will  not  be
           overwritten, but is appended to.
         A toggles in append mode and sets a (second) mark.
         >  sets  the  (second)  mark  and  writes  the  contents  of  the  paste  buffer  to the screen-exchange file
           (/tmp/screen-exchange per default) once copy-mode is finished.
           This example demonstrates how to dump the whole scrollback buffer to that file: "C-A [ g SPACE G $ >".
         C-g gives information about the current line and column.
         x exchanges the first mark and the current cursor position. You can use this  to  adjust  an  already  placed
           mark.
         @ does nothing. Does not even exit copy mode.
         All keys not described here exit copy mode.

       copy_reg [key]

       No longer exists, use "readreg" instead.

       crlf [on|off]

       This  affects  the  copying of text regions with the 'C-a [' command. If it is set to 'on', lines will be sepa-
       rated by the two character sequence 'CR' - 'LF'.  Otherwise (default) only 'LF' is used.  When no parameter  is
       given, the state is toggled.

       debug on|off

       Turns  runtime  debugging on or off. If screen has been compiled with option -DDEBUG debugging available and is
       turned on per default. Note that this command only affects debugging output from the main "SCREEN" process cor-
       rectly. Debug output from attacher processes can only be turned off once and forever.

       defc1 on|off

       Same as the c1 command except that the default setting for new windows is changed. Initial setting is 'on'.

       defautonuke on|off

       Same  as  the  autonuke command except that the default setting for new displays is changed. Initial setting is
       'off'.  Note that you can use the special 'AN' terminal capability if you want to have a dependency on the ter-
       minal type.

       defbce on|off

       Same as the bce command except that the default setting for new windows is changed. Initial setting is 'off'.

       defbreaktype [tcsendbreak|TIOCSBRK |TCSBRK]

       Choose  one  of  the available methods of generating a break signal for terminal devices. The preferred methods
       are tcsendbreak and TIOCSBRK.  The third, TCSBRK, blocks the complete screen session for the  duration  of  the
       break,  but  it  may  be the only way to generate long breaks.  Tcsendbreak and TIOCSBRK may or may not produce
       long breaks with spikes (e.g. 4 per second). This is not only  system  dependant,  this  also  differs  between
       serial board drivers.  Calling "defbreaktype" with no parameter displays the current setting.

       defcharset [set]

       Like  the  charset command except that the default setting for new windows is changed. Shows current default if
       called without argument.

       defescape xy

       Set the default command characters. This is equivalent to the "escape" except that it is useful multiuser  ses-
       sions  only.  In  a  multiuser  session  "escape"  changes  the  command  character  of the calling user, where
       "defescape" changes the default command characters for users that will be added later.

       defflow on|off|auto [interrupt]

       Same as the flow command except that the default setting for new windows is changed. Initial setting is 'auto'.
       Specifying "defflow auto interrupt" is the same as the command-line options -fa and -i.

       defgr on|off

       Same as the gr command except that the default setting for new windows is changed. Initial setting is 'off'.

       defhstatus [status]

       The  hardstatus  line that all new windows will get is set to status.  This command is useful to make the hard-
       status of every window display the window number or title or the like.  Status may contain the same  directives
       as  in  the  window  messages, but the directive escape character is '^E' (octal 005) instead of '%'.  This was
       done to make a misinterpretation of program generated hardstatus lines impossible.  If the parameter status  is
       omitted, the current default string is displayed.  Per default the hardstatus line of new windows is empty.

       defencoding enc

       Same as the encoding command except that the default setting for new windows is changed. Initial setting is the
       encoding taken from the terminal.

       deflog on|off

       Same as the log command except that the default setting for new windows is changed. Initial setting is 'off'.

       deflogin on|off

       Same as the login command except that the default setting for new windows is changed. This is initialized  with
       'on' as distributed (see config.h.in).

       defmode mode

       The  mode  of each newly allocated pseudo-tty is set to mode.  Mode is an octal number.  When no "defmode" com-
       mand is given, mode 0622 is used.

       defmonitor on|off

       Same as the monitor command except that the default setting for new windows  is  changed.  Initial  setting  is
       'off'.

       defnonblock on|off|numsecs

       Same as the nonblock command except that the default setting for displays is changed. Initial setting is 'off'.

       defobuflimit limit

       Same as the obuflimit command except that the default setting for new displays is changed. Initial  setting  is
       256  bytes.  Note that you can use the special 'OL' terminal capability if you want to have a dependency on the
       terminal type.

       defscrollback num

       Same as the scrollback command except that the default setting for new windows is changed. Initial  setting  is
       100.

       defshell command

       Synonym to the shell command. See there.

       defsilence on|off

       Same  as  the  silence  command  except that the default setting for new windows is changed. Initial setting is
       'off'.

       defslowpaste msec"

       Same as the slowpaste command except that the default setting for new windows is changed. Initial setting is  0
       milliseconds, meaning 'off'.

       defutf8 on|off

       Same as the utf8 command except that the default setting for new windows is changed. Initial setting is 'on' if
       screen was started with "-U", otherwise 'off'.

       defwrap on|off

       Same as the wrap command except that the default setting for new windows is changed. Initially line-wrap is  on
       and can be toggled with the "wrap" command ("C-a r") or by means of "C-a : wrap on|off".

       defwritelock on|off|auto

       Same  as the writelock command except that the default setting for new windows is changed. Initially writelocks
       will off.

       defzombie [keys]

       Synonym to the zombie command. Both currently change the default.  See there.

       detach [-h]

       Detach the screen session (disconnect it from the terminal and put it into the background).  This  returns  you
       to  the shell where you invoked screen.  A detached screen can be resumed by invoking screen with the -r option
       (see also section "COMMAND-LINE OPTIONS"). The -h option tells screen to immediately close  the  connection  to
       the terminal ("hangup").

       dinfo

       Show  what  screen thinks about your terminal. Useful if you want to know why features like color or the alter-
       nate charset don't work.

       displays

       Shows a tabular listing of all currently connected user front-ends (displays).  This is most  useful  for  mul-
       tiuser sessions.

       digraph [preset]

       This  command prompts the user for a digraph sequence. The next two characters typed are looked up in a builtin
       table and the resulting character is inserted in the input stream. For example, if the user enters 'a"', an  a-
       umlaut  will be inserted. If the first character entered is a 0 (zero), screen will treat the following charac-
       ters (up to three) as an octal number instead.  The optional argument preset is treated as user input, thus one
       can  create  an "umlaut" key.  For example the command "bindkey ^K digraph '"'" enables the user to generate an
       a-umlaut by typing CTRL-K a.

       dumptermcap

       Write the termcap entry for the virtual terminal optimized for the currently active window to the file  ".term-
       cap"  in  the  user's "$HOME/.screen" directory (or wherever screen stores its sockets. See the "FILES" section
       below).  This termcap entry is identical to the value of the environment variable $TERMCAP that is  set  up  by
       screen  for  each  window.  For terminfo based systems you will need to run a converter like captoinfo and then
       compile the entry with tic.

       echo [-n] message

       The echo command may be used to annoy screen users with a 'message of the day'. Typically installed in a global
       /etc/screenrc.   The option "-n" may be used to suppress the line feed.  See also "sleep".  Echo is also useful
       for online checking of environment variables.

       encoding enc [enc]

       Tell screen how to interpret the input/output. The first argument sets the encoding of the current window. Each
       window can emulate a different encoding. The optional second parameter overwrites the encoding of the connected
       terminal. It should never be needed as screen uses the locale setting to detect the encoding.  There is also  a
       way to select a terminal encoding depending on the terminal type by using the "KJ" termcap entry.

       Supported  encodings  are  eucJP,  SJIS,  eucKR, eucCN, Big5, GBK, KOI8-R, CP1251, UTF-8, ISO8859-2, ISO8859-3,
       ISO8859-4, ISO8859-5, ISO8859-6, ISO8859-7, ISO8859-8, ISO8859-9, ISO8859-10, ISO8859-15, jis.

       See also "defencoding", which changes the default setting of a new window.

       escape xy

       Set the command character to x and the character generating a literal  command  character  (by  triggering  the
       "meta"  command)  to y (similar to the -e option).  Each argument is either a single character, a two-character
       sequence of the form "^x" (meaning "C-x"), a backslash followed by an octal number (specifying the  ASCII  code
       of  the character), or a backslash followed by a second character, such as "\^" or "\\".  The default is "^Aa".

       eval command1 [command2 ...]

       Parses and executes each argument as separate command.

       exec [[fdpat] newcommand [args ...]]

       Run a unix subprocess (specified by an executable path newcommand and its optional arguments)  in  the  current
       window.  The flow of data between newcommands stdin/stdout/stderr, the process originally started in the window
       (let us call it "application-process") and screen itself (window) is controlled by the  filedescriptor  pattern
       fdpat.   This  pattern is basically a three character sequence representing stdin, stdout and stderr of newcom-
       mand. A dot (.) connects the file descriptor to screen.  An exclamation mark (!) causes the file descriptor  to
       be  connected  to  the application-process. A colon (:) combines both.  User input will go to newcommand unless
       newcommand receives the application-process' output (fdpats first character is '!' or ':') or a pipe symbol (|)
       is added (as a fourth character) to the end of fdpat.
       Invoking  'exec' without arguments shows name and arguments of the currently running subprocess in this window.
       Only one subprocess a time can be running in each window.
       When a subprocess is running the 'kill' command will affect it instead of the windows process.
       Refer to the postscript file 'doc/fdpat.ps' for a confusing illustration of all 21 possible combinations.  Each
       drawing shows the digits 2,1,0 representing the three file descriptors of newcommand. The box marked 'W' is the
       usual pty that has the application-process on its slave side.  The box marked 'P' is the secondary pty that now
       has screen at its master side.

       Abbreviations:
       Whitespace between the word 'exec' and fdpat and the command can be omitted. Trailing dots and a fdpat consist-
       ing only of dots can be omitted. A simple '|' is synonymous for the pattern '!..|'; the word exec can be  omit-
       ted here and can always be replaced by '!'.

       Examples:

              exec ... /bin/sh
              exec /bin/sh
              !/bin/sh

       Creates  another  shell in the same window, while the original shell is still running. Output of both shells is
       displayed and user input is sent to the new /bin/sh.

              exec !.. stty 19200
              exec ! stty 19200
              !!stty 19200

       Set the speed of the window's tty. If your stty command operates on stdout, then add another '!'.

              exec !..| less
              |less

       This adds a pager to the window output. The special character '|' is needed to give the user control  over  the
       pager  although  it  gets  its  input  from the window's process. This works, because less listens on stderr (a
       behavior that screen would not expect without the '|') when its stdin is not a tty.  Less versions  newer  than
       177 fail miserably here; good old pg still works.

              !:sed -n s/.*Error.*/\007/p

       Sends  window  output to both, the user and the sed command. The sed inserts an additional bell character (oct.
       007) to the window output seen by screen.  This will cause "Bell in window x"  messages,  whenever  the  string
       "Error" appears in the window.

       fit

       Change  the  window size to the size of the current region. This command is needed because screen doesn't adapt
       the window size automatically if the window is displayed more than once.

       flow [on|off|auto]

       Sets the flow-control mode for this window.  Without parameters it cycles  the  current  window's  flow-control
       setting  from "automatic" to "on" to "off".  See the discussion on "FLOW-CONTROL" later on in this document for
       full details and note, that this is subject to change in future releases.  Default is set by 'defflow'.

       focus [up|down|top|bottom]

       Move the input focus to the next region. This is done in a cyclic way so that the top region is selected  after
       the  bottom  one. If no subcommand is given it defaults to 'down'. 'up' cycles in the opposite order, 'top' and
       'bottom' go to the top and bottom region respectively. Useful bindings are (j and k as in vi)
           bind j focus down
           bind k focus up
           bind t focus top
           bind b focus bottom

       gr [on|off]

       Turn GR charset switching on/off. Whenever screen sees an input character with the 8th bit set, it will use the
       charset stored in the GR slot and print the character with the 8th bit stripped. The default (see also "defgr")
       is not to process GR switching because otherwise the ISO88591 charset would not work.

       hardcopy [-h] [file]

       Writes out the currently displayed image to the file file, or, if no filename is specified,  to  hardcopy.n  in
       the default directory, where n is the number of the current window.  This either appends or overwrites the file
       if it exists. See below.  If the option -h is specified, dump also the contents of the scrollback buffer.

       hardcopy_append on|off

       If set to "on", screen will append to the "hardcopy.n" files created by the command "C-a  h",  otherwise  these
       files are overwritten each time.  Default is 'off'.

       hardcopydir directory

       Defines  a  directory  where  hardcopy files will be placed. If unset, hardcopys are dumped in screen's current
       working directory.

       hardstatus [on|off]
       hardstatus [always]lastline|message|ignore [string]
       hardstatus string [string]

       This command configures the use and emulation of the terminal's hardstatus line. The first form toggles whether
       screen  will  use the hardware status line to display messages. If the flag is set to 'off', these messages are
       overlaid in reverse video mode at the display line. The default setting is 'on'.

       The second form  tells  screen  what  to  do  if  the  terminal  doesn't  have  a  hardstatus  line  (i.e.  the
       termcap/terminfo  capabilities  "hs",  "ts", "fs" and "ds" are not set). If the type "lastline" is used, screen
       will reserve the last line of the display for the hardstatus. "message" uses  screen's  message  mechanism  and
       "ignore"  tells  screen  never  to display the hardstatus.  If you prepend the word "always" to the type (e.g.,
       "alwayslastline"), screen will use the type even if the terminal supports a hardstatus.

       The third form specifies the contents of the hardstatus line.  '%h' is used as default string, i.e. the  stored
       hardstatus of the current window (settable via "ESC]0;<string>^G" or "ESC_<string>ESC\") is displayed.  You can
       customize this to any string you like including the escapes from the "STRING ESCAPES" chapter. If you leave out
       the argument string, the current string is displayed.

       You can mix the second and third form by providing the string as additional argument.

       height [-w|-d] [lines [cols]]

       Set  the  display height to a specified number of lines. When no argument is given it toggles between 24 and 42
       lines display. You can also specify a width if you want to change both values.  The -w option tells  screen  to
       leave the display size unchanged and just set the window size, -d vice versa.

       help [-c class]

       Not  really  a  online help, but displays a help screen showing you all the key bindings.  The first pages list
       all the internal commands followed by their current bindings.  Subsequent pages will display  the  custom  com-
       mands,  one  command  per  key.   Press space when you're done reading each page, or return to exit early.  All
       other characters are ignored. If the "-c" option is given, display all bound commands for the specified command
       class.  See also "DEFAULT KEY BINDINGS" section.

       history

       Usually  users work with a shell that allows easy access to previous commands.  For example csh has the command
       "!!" to repeat the last command executed.  Screen allows you to have a primitive way of re-calling "the command
       that  started ...": You just type the first letter of that command, then hit 'C-a {' and screen tries to find a
       previous line that matches with the 'prompt character' to the left of the cursor. This line is pasted into this
       window's  input queue.  Thus you have a crude command history (made up by the visible window and its scrollback
       buffer).

       hstatus status

       Change the window's hardstatus line to the string status.

       idle [timeout [cmd args]]

       Sets a command that is run after the specified number of seconds inactivity is reached. This command will  nor-
       mally  be the "blanker" command to create a screen blanker, but it can be any screen command.  If no command is
       specified, only the timeout is set. A timeout of zero (ot the special timeout off) disables the timer.   If  no
       arguments are given, the current settings are displayed.

       ignorecase [on|off]

       Tell screen to ignore the case of characters in searches. Default is 'off'.

       info

       Uses  the  message  line  to display some information about the current window: the cursor position in the form
       "(column,row)" starting with "(1,1)", the terminal width and height plus the size of the scrollback  buffer  in
       lines,  like  in  "(80,24)+50",  the current state of window XON/XOFF flow control is shown like this (See also
       section FLOW CONTROL):

         +flow     automatic flow control, currently on.
         -flow     automatic flow control, currently off.
         +(+)flow  flow control enabled. Agrees with automatic control.
         -(+)flow  flow control disabled. Disagrees with automatic control.
         +(-)flow  flow control enabled. Disagrees with automatic control.
         -(-)flow  flow control disabled. Agrees with automatic control.

       The current line wrap setting ('+wrap' indicates enabled, '-wrap' not) is also shown. The flags  'ins',  'org',
       'app', 'log', 'mon' or 'nored' are displayed when the window is in insert mode, origin mode, application-keypad
       mode, has output logging, activity monitoring or partial redraw enabled.

       The currently active character set (G0, G1, G2, or G3) and in square brackets the terminal character sets  that
       are currently designated as G0 through G3 is shown. If the window is in UTF-8 mode, the string "UTF-8" is shown
       instead.

       Additional modes depending on the type of the window are displayed at the end of  the  status  line  (See  also
       chapter "WINDOW TYPES").
       If the state machine of the terminal emulator is in a non-default state, the info line is started with a string
       identifying the current state.
       For system information use the "time" command.

       ins_reg [key]

       No longer exists, use "paste" instead.

       kill

       Kill current window.
       If there is an 'exec' command running then it is killed. Otherwise the process (shell) running  in  the  window
       receives a HANGUP condition, the window structure is removed and screen (your display) switches to another win-
       dow.  When the last window is destroyed, screen exits.  After a kill screen switches  to  the  previously  dis-
       played window.
       Note: Emacs users should keep this command in mind, when killing a line.  It is recommended not to use "C-a" as
       the screen escape key or to rebind kill to "C-a K".

       lastmsg

       Redisplay the last contents of the message/status line.  Useful  if  you're  typing  when  a  message  appears,
       because   the  message goes away when you press a key (unless your terminal has a hardware status line).  Refer
       to the commands "msgwait" and "msgminwait" for fine tuning.

       license

       Display the disclaimer page. This is done whenever screen is started without options,  which  should  be  often
       enough. See also the "startup_message" command.

       lockscreen

       Lock  this  display.   Call  a  screenlock program (/local/bin/lck or /usr/bin/lock or a builtin if no other is
       available). Screen does not accept any command keys until this program terminates. Meanwhile processes  in  the
       windows may continue, as the windows are in the 'detached' state. The screenlock program may be changed through
       the environment variable $LOCKPRG (which must be set in the shell from which screen is started) and is executed
       with the user's uid and gid.
       Warning:  When  you  leave  other shells unlocked and you have no password set on screen, the lock is void: One
       could easily re-attach from an unlocked shell. This feature should rather be called 'lockterminal'.

       log [on|off]

       Start/stop writing output of the current window to a file "screenlog.n"  in  the  window's  default  directory,
       where  n  is  the  number of the current window. This filename can be changed with the 'logfile' command. If no
       parameter is given, the state of logging is toggled. The session log is appended to the  previous  contents  of
       the file if it already exists. The current contents and the contents of the scrollback history are not included
       in the session log.  Default is 'off'.

       logfile filename
       logfile flush secs

       Defines the name the logfiles will get. The default is "screenlog.%n". The second form changes  the  number  of
       seconds  screen  will  wait before flushing the logfile buffer to the file-system. The default value is 10 sec-
       onds.

       login [on|off]

       Adds or removes the entry in the utmp database file for the current window.  This controls  if  the  window  is
       'logged  in'.  When no parameter is given, the login state of the window is toggled.  Additionally to that tog-
       gle, it is convenient having a 'log in' and a 'log out' key. E.g. 'bind I login on' and 'bind O login off' will
       map  these  keys  to be C-a I and C-a O.  The default setting (in config.h.in) should be "on" for a screen that
       runs under suid-root.  Use the "deflogin" command to change the default login state for new windows. Both  com-
       mands are only present when screen has been compiled with utmp support.

       logtstamp [on|off]
       logtstamp after [secs]
       logtstamp string [string]

       This  command  controls  logfile time-stamp mechanism of screen.  If time-stamps are turned "on", screen adds a
       string containing the current time to the logfile after two minutes of inactivity.  When output  continues  and
       more  than another two minutes have passed, a second time-stamp is added to document the restart of the output.
       You can change this timeout with the second form of the command. The third form is  used  for  customizing  the
       time-stamp string ('-- %n:%t -- time-stamp -- %M/%d/%y %c:%s --\n' by default).

       mapdefault

       Tell  screen  that  the  next  input  character should only be looked up in the default bindkey table. See also
       "bindkey".

       mapnotnext

       Like mapdefault, but don't even look in the default bindkey table.

       maptimeout [timo]

       Set the inter-character timer for input sequence detection to a timeout of timo  ms.  The  default  timeout  is
       300ms. Maptimeout with no arguments shows the current setting.  See also "bindkey".

       markkeys string

       This  is  a method of changing the keymap used for copy/history mode.  The string is made up of oldchar=newchar
       pairs which are separated by ':'. Example: The string "B=^B:F=^F" will change the keys 'C-b' and 'C-f'  to  the
       vi style binding (scroll up/down fill page).  This happens to be the default binding for 'B' and 'F'.  The com-
       mand "markkeys h=^B:l=^F:$=^E" would set the mode for an emacs-style binding.  If your terminal  sends  charac-
       ters,  that cause you to abort copy mode, then this command may help by binding these characters to do nothing.
       The no-op character is '@' and is used like this: "markkeys @=L=H" if you do not want to use  the  'H'  or  'L'
       commands  any  longer.   As  shown  in  this example, multiple keys can be assigned to one function in a single
       statement.

       maxwin num

       Set the maximum window number screen will create. Doesn't affect already existing windows. The number may  only
       be decreased.

       meta

       Insert the command character (C-a) in the current window's input stream.

       monitor [on|off]

       Toggles  activity  monitoring of windows.  When monitoring is turned on and an affected window is switched into
       the background, you will receive the activity notification message in the status line at the first sign of out-
       put  and  the window will also be marked with an '@' in the window-status display.  Monitoring is initially off
       for all windows.

       msgminwait sec

       Defines the time screen delays a new message when one message is currently displayed.  The default is 1 second.

       msgwait sec

       Defines the time a message is displayed if screen is not disturbed by other activity. The default is 5 seconds.

       multiuser on|off

       Switch between singleuser and multiuser mode. Standard screen operation is singleuser. In  multiuser  mode  the
       commands  'acladd',  'aclchg',  'aclgrp' and 'acldel' can be used to enable (and disable) other users accessing
       this screen session.

       nethack on|off

       Changes the kind of error messages used by screen.  When you are familiar with  the  game  "nethack",  you  may
       enjoy  the  nethack-style messages which will often blur the facts a little, but are much funnier to read. Any-
       way, standard messages often tend to be unclear as well.
       This option is only available if screen was compiled with the NETHACK flag defined. The default setting is then
       determined by the presence of the environment variable $NETHACKOPTIONS.

       next

       Switch to the next window.  This command can be used repeatedly to cycle through the list of windows.

       nonblock [on|off|numsecs]

       Tell  screen how to deal with user interfaces (displays) that cease to accept output. This can happen if a user
       presses ^S or a TCP/modem connection gets cut but no hangup is received.  If  nonblock  is  off  (this  is  the
       default)  screen  waits  until the display restarts to accept the output. If nonblock is on, screen waits until
       the timeout is reached (on is treated as 1s). If the display still doesn't receive characters, screen will con-
       sider  it "blocked" and stop sending characters to it. If at some time it restarts to accept characters, screen
       will unblock the display and redisplay the updated window contents.

       number [n]

       Change the current windows number. If the given number n is  already  used  by  another  window,  both  windows
       exchange their numbers. If no argument is specified, the current window number (and title) is shown.

       obuflimit [limit]

       If  the output buffer contains more bytes than the specified limit, no more data will be read from the windows.
       The default value is 256. If you have a fast display (like xterm), you can set it to some higher value.  If  no
       argument is specified, the current setting is displayed.

       only

       Kill all regions but the current one.

       other

       Switch  to  the  window displayed previously. If this window does no longer exist, other has the same effect as
       next.

       partial on|off

       Defines whether the display should be refreshed (as with redisplay) after switching to the current window. This
       command  only  affects  the  current  window.   To  immediately  affect all windows use the allpartial command.
       Default is 'off', of course.  This default is fixed, as there is currently no defpartial command.

       password [crypted_pw]

       Present a crypted password in your ".screenrc" file and screen will ask for it, whenever  someone  attempts  to
       resume  a detached. This is useful if you have privileged programs running under screen and you want to protect
       your session from reattach attempts by another user masquerading as your  uid  (i.e.  any  superuser.)   If  no
       crypted  password  is  specified,  screen  prompts twice for typing a password and places its encryption in the
       paste buffer.  Default is 'none', this disables password checking.

       paste [registers [dest_reg]]

       Write the (concatenated) contents of the specified registers to the stdin queue of the current window. The reg-
       ister  '.'  is treated as the paste buffer. If no parameter is given the user is prompted for a single register
       to paste.  The paste buffer can be filled with the copy, history and readbuf commands.  Other registers can  be
       filled  with the register, readreg and paste commands.  If paste is called with a second argument, the contents
       of the specified registers is pasted into the named destination register rather than the window. If '.' is used
       as  the  second argument, the displays paste buffer is the destination.  Note, that "paste" uses a wide variety
       of resources: Whenever a second argument is specified no current window is needed. When the  source  specifica-
       tion  only  contains  registers  (not  the  paste  buffer)  then  there need not be a current display (terminal
       attached), as the registers are a global resource. The paste buffer exists once for every user.

       pastefont [on|off]

       Tell screen to include font information in the paste buffer. The default is not to do so. This command is espe-
       cially useful for multi character fonts like kanji.

       pow_break

       Reopen the window's terminal line and send a break condition. See 'break'.

       pow_detach

       Power detach.  Mainly the same as detach, but also sends a HANGUP signal to the parent process of screen.  CAU-
       TION: This will result in a logout, when screen was started from your login shell.

       pow_detach_msg [message]

       The message specified here is output whenever a 'Power detach' was performed. It may be used as  a  replacement
       for a logout message or to reset baud rate, etc.  Without parameter, the current message is shown.

       prev

       Switch to the window with the next lower number.  This command can be used repeatedly to cycle through the list
       of windows.

       printcmd [cmd]

       If cmd is not an empty string, screen will not use the terminal capabilities "po/pf"  if  it  detects  an  ansi
       print  sequence ESC [ 5 i, but pipe the output into cmd.  This should normally be a command like "lpr" or "'cat
       > /tmp/scrprint'".  printcmd without a command displays the current setting.  The  ansi  sequence  ESC  \  ends
       printing and closes the pipe.
       Warning:  Be  careful with this command! If other user have write access to your terminal, they will be able to
       fire off print commands.

       process [key]

       Stuff the contents of the specified register into screen's input  queue.  If  no  argument  is  given  you  are
       prompted for a register name. The text is parsed as if it had been typed in from the user's keyboard. This com-
       mand can be used to bind multiple actions to a single key.

       quit

       Kill all windows and terminate screen.  Note that on VT100-style terminals the keys C-4 and C-\ are  identical.
       This makes the default bindings dangerous: Be careful not to type C-a C-4 when selecting window no. 4.  Use the
       empty bind command (as in "bind '^\'") to remove a key binding.

       readbuf [-e encoding] [filename]

       Reads the contents of the specified file into the paste buffer.  You can tell screen the encoding of  the  file
       via  the -e option.  If no file is specified, the screen-exchange filename is used.  See also "bufferfile" com-
       mand.

       readreg [-e encoding] [register [filename]]

       Does one of two things, dependent on number of arguments: with zero or one arguments it it duplicates the paste
       buffer  contents into the register specified or entered at the prompt. With two arguments it reads the contents
       of the named file into the register, just as readbuf reads the screen-exchange file into the paste buffer.  You
       can  tell  screen  the  encoding  of the file via the -e option.  The following example will paste the system's
       password file into the screen window (using register p, where a copy remains):

                   C-a : readreg p /etc/passwd
                   C-a : paste p

       redisplay

       Redisplay the current window. Needed to get a full redisplay when in partial redraw mode.

       register [-e encoding] key string

       Save the specified string to the register key.  The encoding of the string can be specified via the -e  option.
       See also the "paste" command.

       remove

       Kill the current region. This is a no-op if there is only one region.

       removebuf

       Unlinks the screen-exchange file used by the commands "writebuf" and "readbuf".

       reset

       Reset  the  virtual  terminal  to  its  "power-on" values. Useful when strange settings (like scroll regions or
       graphics character set) are left over from an application.

       resize

       Resize the current region. The space will be removed from or added to the region below or if there's not enough
       space from the region above.

              resize +N   increase current region height by N

              resize -N   decrease current region height by N

              resize  N   set current region height to N

              resize  =   make all windows equally high

              resize  max maximize current region height

              resize  min minimize current region height


       screen [-opts] [n] [cmd [args]]

       Establish  a new window.  The flow-control options (-f, -fn and -fa), title (a.k.a.) option (-t), login options
       (-l and -ln) , terminal type option (-T <term>), the all-capability-flag (-a) and scrollback option (-h  <num>)
       may  be  specified  with  each  command.  The option (-M) turns monitoring on for this window.  The option (-L)
       turns output logging on for this window.  If an optional number n in the range 0..9 is given, the window number
       n  is  assigned  to the newly created window (or, if this number is already in-use, the next available number).
       If a command is specified after "screen", this command (with the given arguments) is  started  in  the  window;
       otherwise, a shell is created.  Thus, if your ".screenrc" contains the lines

                   # example for .screenrc:
                   screen 1
                   screen -fn -t foobar -L 2 telnet foobar

       screen  creates a shell window (in window #1) and a window with a TELNET connection to the machine foobar (with
       no flow-control using the title "foobar" in window #2) and will write a logfile ("screenlog.2") of  the  telnet
       session.   Note,  that unlike previous versions of screen no additional default window is created when "screen"
       commands are included in your ".screenrc" file. When the initialization is completed, screen  switches  to  the
       last window specified in your .screenrc file or, if none, opens a default window #0.
       Screen has built in some functionality of "cu" and "telnet".  See also chapter "WINDOW TYPES".

       scrollback num

       Set  the  size  of  the  scrollback  buffer for the current windows to num lines. The default scrollback is 100
       lines.  See also the "defscrollback" command and use "C-a i" to view the current setting.

       select [WindowID]

       Switch to the window identified by WindowID.  This can be a prefix of a window title (alphanumeric window name)
       or  a window number.  The parameter is optional and if omitted, you get prompted for an identifier.  When a new
       window is established, the first available number is assigned to this window.  Thus, the first  window  can  be
       activated  by "select 0".  The number of windows is limited at compile-time by the MAXWIN configuration parame-
       ter.  There are two special WindowIDs, "-" selects the internal blank window and "." selects the  current  win-
       dow. The latter is useful if used with screen's "-X" option.

       sessionname [name]

       Rename  the  current session. Note, that for "screen -list" the name shows up with the process-id prepended. If
       the argument "name" is omitted, the name of this session is displayed. Caution: The $STY environment  variables
       still  reflects  the  old name. This may result in confusion.  The default is constructed from the tty and host
       names.

       setenv [var [string]]

       Set the environment variable var to value string.  If only var is specified, the user will be prompted to enter
       a  value.   If no parameters are specified, the user will be prompted for both variable and value. The environ-
       ment is inherited by all subsequently forked shells.

       setsid [on|off]

       Normally screen uses different sessions and process groups for the windows. If setsid is turned  off,  this  is
       not  done  anymore  and  all windows will be in the same process group as the screen backend process. This also
       breaks job-control, so be careful.  The default is on, of course. This command is probably useful only in  rare
       circumstances.

       shell command

       Set the command to be used to create a new shell.  This overrides the value of the environment variable $SHELL.
       This is useful if you'd like to run a tty-enhancer which is expecting  to  execute  the  program  specified  in
       $SHELL. If the command begins with a '-' character, the shell will be started as a login-shell.

       shelltitle title

       Set  the title for all shells created during startup or by the C-A C-c command.  For details about what a title
       is, see the discussion entitled "TITLES (naming windows)".

       silence [on|off|sec]

       Toggles silence monitoring of windows.  When silence is turned on and an affected window is switched  into  the
       background,  you  will  receive the silence notification message in the status line after a specified period of
       inactivity (silence). The default timeout can be changed with the 'silencewait' command or by specifying a num-
       ber of seconds instead of 'on' or 'off'.  Silence is initially off for all windows.

       silencewait sec

       Define the time that all windows monitored for silence should wait before displaying a message. Default 30 sec-
       onds.

       sleep num

       This command will pause the execution of a .screenrc file for num seconds.   Keyboard  activity  will  end  the
       sleep.  It may be used to give users a chance to read the messages output by "echo".

       slowpaste msec

       Define  the  speed  at  which  text is inserted into the current window by the paste ("C-a ]") command.  If the
       slowpaste value is nonzero text is written character by character.  screen will make a pause of msec  millisec-
       onds  after  each  single  character write to allow the application to process its input. Only use slowpaste if
       your underlying system exposes flow control problems while pasting large amounts of text.

       source file

       Read and execute commands from file file. Source commands may be nested to a maximum recursion level of ten. If
       file  is  not  an  absolute path and screen is already processing a source command, the parent directory of the
       running source command file is used to search for the new command file before screen's current directory.

       Note that termcap/terminfo/termcapinfo commands only work at startup and reattach time, so they must be reached
       via the default screenrc files to have an effect.

       sorendition [attr [color]]

       Change the way screen does highlighting for text marking and printing messages.  See the "STRING ESCAPES" chap-
       ter for the syntax of the modifiers.  The default is currently "=s dd" (standout, default colors).

       split

       Split the current region into two new ones. All regions on the display are resized to make  room  for  the  new
       region.  The  blank  window  is  displayed  on the new region. Use the "remove" or the "only" command to delete
       regions.

       startup_message on|off

       Select whether you want to see the copyright notice during startup.  Default is 'on', as you probably  noticed.

       stuff string

       Stuff  the  string string in the input buffer of the current window.  This is like the "paste" command but with
       much less overhead.  You cannot paste large buffers with the "stuff" command. It is most useful for  key  bind-
       ings. See also "bindkey".

       su [username [password [password2]]

       Substitute  the  user  of  a display. The command prompts for all parameters that are omitted. If passwords are
       specified as parameters, they have to be specified un-crypted. The first password is matched against  the  sys-
       tems  passwd  database,  the  second  password  is matched against the screen password as set with the commands
       "acladd" or "password".  "Su" may be useful for the screen administrator to test multiuser  setups.   When  the
       identification  fails,  the  user  has  access  to the commands available for user nobody.  These are "detach",
       "license", "version", "help" and "displays".

       suspend

       Suspend screen.  The windows are in the 'detached' state, while screen is suspended. This feature relies on the
       shell being able to do job control.

       term term

       In  each  window's  environment  screen  opens,  the $TERM variable is set to "screen" by default.  But when no
       description for "screen" is installed in the local termcap or terminfo data base, you set  $TERM  to  -  say  -
       "vt100".  This  won't  do much harm, as screen is VT100/ANSI compatible.  The use of the "term" command is dis-
       couraged for non-default purpose.  That is, one may want to specify special $TERM settings (e.g. vt100) for the
       next  "screen  rlogin  othermachine" command. Use the command "screen -T vt100 rlogin othermachine" rather than
       setting and resetting the default.

       termcap term terminal-tweaks [window-tweaks]
       terminfo term terminal-tweaks [window-tweaks]
       termcapinfo term terminal-tweaks [window-tweaks]

       Use this command to modify your terminal's termcap entry without going through all the hassles involved in cre-
       ating  a  custom termcap entry.  Plus, you can optionally customize the termcap generated for the windows.  You
       have to place these commands in one of the screenrc startup files, as they are meaningless  once  the  terminal
       emulator is booted.
       If your system works uses the terminfo database rather than termcap, screen will understand the 'terminfo' com-
       mand, which has the same effects as the 'termcap' command.  Two separate commands are provided,  as  there  are
       subtle  syntactic  differences,  e.g.  when  parameter interpolation (using '%') is required. Note that termcap
       names of the capabilities have to be used with the 'terminfo' command.
       In many cases, where the arguments are valid in both terminfo and termcap  syntax,  you  can  use  the  command
       'termcapinfo',  which  is just a shorthand for a pair of 'termcap' and 'terminfo' commands with identical argu-
       ments.

       The first argument specifies which terminal(s) should be affected by this definition.  You can specify multiple
       terminal  names  by separating them with '|'s.  Use '*' to match all terminals and 'vt*' to match all terminals
       that begin with "vt".

       Each tweak argument contains one or more termcap defines (separated by ':'s) to be inserted at the start of the
       appropriate  termcap  entry,  enhancing it or overriding existing values.  The first tweak modifies your termi-
       nal's termcap, and contains definitions that your terminal uses to perform certain functions.  Specify  a  null
       string  to  leave  this unchanged (e.g. '').  The second (optional) tweak modifies all the window termcaps, and
       should contain definitions that screen understands (see the "VIRTUAL TERMINAL" section).

       Some examples:

              termcap xterm*  LP:hs@

       Informs screen that all terminals that begin with 'xterm' have firm auto-margins that allow the  last  position
       on  the  screen  to  be  updated  (LP),  but they don't really have a status line (no 'hs' - append '@' to turn
       entries off).  Note that we assume 'LP' for all terminal names that start with "vt",  but  only  if  you  don't
       specify a termcap command for that terminal.

              termcap vt*  LP
              termcap vt102|vt220  Z0=\E[?3h:Z1=\E[?3l

       Specifies  the  firm-margined  'LP' capability for all terminals that begin with 'vt', and the second line will
       also add the escape-sequences to switch into (Z0) and back out of (Z1) 132-character-per-line mode if this is a
       VT102 or VT220.  (You must specify Z0 and Z1 in your termcap to use the width-changing commands.)

              termcap vt100  ""  l0=PF1:l1=PF2:l2=PF3:l3=PF4

       This leaves your vt100 termcap alone and adds the function key labels to each window's termcap entry.

              termcap h19|z19  am@:im=\E@:ei=\EO  dc=\E[P

       Takes  a  h19  or  z19 termcap and turns off auto-margins (am@) and enables the insert mode (im) and end-insert
       (ei) capabilities (the '@' in the 'im' string is after the '=', so it is part of the string).  Having the  'im'
       and  'ei' definitions put into your terminal's termcap will cause screen to automatically advertise the charac-
       ter-insert capability in each window's termcap.  Each window will also get the delete-character capability (dc)
       added  to  its  termcap,  which  screen will translate into a line-update for the terminal (we're pretending it
       doesn't support character deletion).

       If you would like to fully specify each window's termcap entry, you should instead set the $SCREENCAP  variable
       prior  to  running screen.  See the discussion on the "VIRTUAL TERMINAL" in this manual, and the termcap(5) man
       page for more information on termcap definitions.

       time [string]

       Uses the message line to display the time of day, the host name, and the load averages over 1, 5, and  15  min-
       utes (if this is available on your system).  For window specific information use "info".

       If a string is specified, it changes the format of the time report like it is described in the "STRING ESCAPES"
       chapter. Screen uses a default of "%c:%s %M %d %H%? %l%?".

       title [windowtitle]

       Set the name of the current window to windowtitle. If no name is specified, screen prompts for one.  This  com-
       mand was known as 'aka' in previous releases.

       unsetenv var

       Unset an environment variable.

       utf8 [on|off [on|off]]

       Change  the  encoding  used  in  the current window. If utf8 is enabled, the strings sent to the window will be
       UTF-8 encoded and vice versa. Omitting the parameter toggles the setting. If a second parameter is  given,  the
       display's encoding is also changed (this should rather be done with screen's "-U" option).  See also "defutf8",
       which changes the default setting of a new window.

       vbell [on|off]

       Sets the visual bell setting for this window. Omitting the parameter toggles the setting. If vbell is  switched
       on,  but  your  terminal does not support a visual bell, a 'vbell-message' is displayed in the status line when
       the bell character (^G) is received.  Visual bell support of a terminal is defined by the termcap variable 'vb'
       (terminfo: 'flash').
       Per default, vbell is off, thus the audible bell is used.  See also 'bell_msg'.

       vbell_msg [message]

       Sets  the  visual  bell  message. message is printed to the status line if the window receives a bell character
       (^G), vbell is set to "on", but the terminal does not support a visual bell.  The  default  message  is  "Wuff,
       Wuff!!".  Without parameter, the current message is shown.

       vbellwait sec

       Define a delay in seconds after each display of screen's visual bell message. The default is 1 second.

       verbose [on|off]

       If verbose is switched on, the command name is echoed, whenever a window is created (or resurrected from zombie
       state). Default is off.  Without parameter, the current setting is shown.

       version

       Print the current version and the compile date in the status line.

       wall message

       Write a message to all displays. The message will appear in the terminal's status line.

       width [-w|-d] [cols [lines]]

       Toggle the window width between 80 and 132 columns or set it to cols columns if an argument is specified.  This
       requires a capable terminal and the termcap entries "Z0" and "Z1".  See the "termcap" command for more informa-
       tion. You can also specify a new height if you want to change both values.  The -w option tells screen to leave
       the display size unchanged and just set the window size, -d vice versa.

       windowlist [-b] [-m]
       windowlist string [string]
       windowlist title [title]

       Display all windows in a table for visual window selection. The desired window can be selected via the standard
       movement keys (see the "copy" command) and activated via the return key.  If the -b  option  is  given,  screen
       will switch to the blank window before presenting the list, so that the current window is also selectable.  The
       -m option changes the order of the windows, instead of sorting by window numbers screen uses its internal most-
       recently-used list.

       The  table  format  can  be  changed with the string and title option, the title is displayed as table heading,
       while the lines are made by using the string setting. The default setting is "Num Name%=Flags"  for  the  title
       and "%3n %t%=%f" for the lines.  See the "STRING ESCAPES" chapter for more codes (e.g. color settings).

       windows

       Uses  the  message line to display a list of all the windows.  Each window is listed by number with the name of
       process that has been started in the window (or its title); the current window is marked with a '*'; the previ-
       ous  window is marked with a '-'; all the windows that are "logged in" are marked with a '$'; a background win-
       dow that has received a bell is marked with a '!'; a background window that is  being  monitored  and  has  had
       activity occur is marked with an '@'; a window which has output logging turned on is marked with '(L)'; windows
       occupied by other users are marked with '&'; windows in the zombie state are marked with 'Z'.  If this list  is
       too long to fit on the terminal's status line only the portion around the current window is displayed.

       wrap [on|off]

       Sets  the  line-wrap  setting  for  the current window.  When line-wrap is on, the second consecutive printable
       character output at the last column of a line will wrap to the start of the following line.  As an  added  fea-
       ture, backspace (^H) will also wrap through the left margin to the previous line.  Default is 'on'.

       writebuf [-e encoding] [filename]

       Writes the contents of the paste buffer to the specified file, or the public accessible screen-exchange file if
       no filename is given. This is thought of as a primitive means of communication between screen users on the same
       host.  If  an encoding is specified the paste buffer is recoded on the fly to match the encoding.  The filename
       can be set with the bufferfile command and defaults to "/tmp/screen-exchange".

       writelock [on|off|auto]

       In addition to access control lists, not all users may be able to  write  to  the  same  window  at  once.  Per
       default,  writelock  is  in  'auto'  mode and grants exclusive input permission to the user who is the first to
       switch to the particular window. When he leaves the window, other users may  obtain  the  writelock  (automati-
       cally).  The writelock of the current window is disabled by the command "writelock off". If the user issues the
       command "writelock on" he keeps the exclusive write permission while switching to other windows.

       xoff
       xon

       Insert a CTRL-s / CTRL-q character to the stdin queue of the current window.

       zmodem [off|auto|catch|pass]
       zmodem sendcmd [string]
       zmodem recvcmd [string]

       Define zmodem support for screen. Screen understands two different modes when  it  detects  a  zmodem  request:
       "pass"  and "catch".  If the mode is set to "pass", screen will relay all data to the attacher until the end of
       the transmission is reached.  In "catch" mode screen acts as a zmodem endpoint  and  starts  the  corresponding
       rz/sz  commands.  If  the  mode is set to "auto", screen will use "catch" if the window is a tty (e.g. a serial
       line), otherwise it will use "pass".
       You can define the templates screen uses in "catch" mode via the second and the third form.
       Note also that this is an experimental feature.

       zombie [keys]
       defzombie [keys]

       Per default screen windows are removed from the window list as soon as the windows process (e.g. shell)  exits.
       When a string of two keys is specified to the zombie command, 'dead' windows will remain in the list.  The kill
       command may be used to remove such a window. Pressing the first key in the dead window  has  the  same  effect.
       When  pressing the second key, screen will attempt to resurrect the window. The process that was initially run-
       ning in the window will be launched again. Calling zombie without parameters will  clear  the  zombie  setting,
       thus making windows disappear when their process exits.

       As  the  zombie-setting  is manipulated globally for all windows, this command should only be called defzombie.
       Until we need this as a per window setting, the commands zombie and defzombie are synonymous.


THE MESSAGE LINE
       Screen displays informational messages and other diagnostics in a message line.  While this line is distributed
       to appear at the bottom of the screen, it can be defined to appear at the top of the screen during compilation.
       If your terminal has a status line defined in its termcap, screen will use this for  displaying  its  messages,
       otherwise  a  line  of the current screen will be temporarily overwritten and output will be momentarily inter-
       rupted. The message line is automatically removed after a few seconds delay, but it can also be  removed  early
       (on terminals without a status line) by beginning to type.

       The message line facility can be used by an application running in the current window by means of the ANSI Pri-
       vacy message control sequence.  For instance, from within the shell, try something like:

              echo '<esc>^Hello world from window '$WINDOW'<esc>\\'

       where '<esc>' is an escape, '^' is a literal up-arrow, and '\\' turns into a single backslash.


WINDOW TYPES
       Screen provides three different window types. New windows are created with screen's screen  command  (see  also
       the  entry  in chapter "CUSTOMIZATION"). The first parameter to the screen command defines which type of window
       is created. The different window types are all special cases of the normal type. They have been added in  order
       to allow screen to be used efficiently as a console multiplexer with 100 or more windows.


       ?  The  normal  window  contains  a  shell (default, if no parameter is given) or any other system command that
          could be executed from a shell (e.g.  slogin, etc...)


       ?  If a tty (character special device) name (e.g. "/dev/ttya") is specified as the first  parameter,  then  the
          window is directly connected to this device.  This window type is similar to "screen cu -l /dev/ttya".  Read
          and write access is required on the device node, an exclusive open is attempted on the node to mark the con-
          nection line as busy.  An optional parameter is allowed consisting of a comma separated list of flags in the
          notation used by stty(1):

          <baud_rate>
                 Usually 300, 1200, 9600 or 19200. This affects transmission as well as receive speed.

          cs8 or cs7
                 Specify the transmission of eight (or seven) bits per byte.

          ixon or -ixon
                 Enables (or disables) software flow-control (CTRL-S/CTRL-Q) for sending data.

          ixoff or -ixon
                 Enables (or disables) software flow-control for receiving data.

          istrip or -istrip
                 Clear (or keep) the eight bit in each received byte.

          You may want to specify as many of these options as  applicable.  Unspecified  options  cause  the  terminal
          driver  to  make up the parameter values of the connection.  These values are system dependant and may be in
          defaults or values saved from a previous connection.

          For tty windows, the info command shows some of the modem control  lines  in  the  status  line.  These  may
          include  'RTS',  'CTS',  'DTR',  'DSR',  'CD'  and more.  This depends on the available ioctl()'s and system
          header files as well as the on the physical capabilities of the serial board.  Signals that are logical  low
          (inactive)  have  their  name  preceded  by  an  exclamation  mark (!), otherwise the signal is logical high
          (active).  Signals not supported by the hardware but available to the ioctl() interface  are  usually  shown
          low.
          When  the CLOCAL status bit is true, the whole set of modem signals is placed inside curly braces ({ and }).
          When the CRTSCTS or TIOCSOFTCAR bit is set, the signals 'CTS' or 'CD'  are  shown  in  parenthesis,  respec-
          tively.


          For  tty windows, the command break causes the Data transmission line (TxD) to go low for a specified period
          of time. This is expected to be interpreted as break signal on the other side.  No data is sent and no modem
          control line is changed when a break is issued.

       ?  If  the  first  parameter is "//telnet", the second parameter is expected to be a host name, and an optional
          third parameter may specify a TCP port number (default decimal 23).  Screen will connect to a server listen-
          ing on the remote host and use the telnet protocol to communicate with that server.
          For  telnet windows, the command info shows details about the connection in square brackets ([ and ]) at the
          end of the status line.

          b      BINARY. The connection is in binary mode.

          e      ECHO. Local echo is disabled.

          c      SGA. The connection is in 'character mode' (default: 'line mode').

          t      TTYPE. The terminal type has been requested by the remote  host.   Screen  sends  the  name  "screen"
                 unless instructed otherwise (see also the command 'term').

          w      NAWS. The remote site is notified about window size changes.

          f      LFLOW. The remote host will send flow control information.  (Ignored at the moment.)

          Additional flags for debugging are x, t and n (XDISPLOC, TSPEED and NEWENV).

          For telnet windows, the command break sends the telnet code IAC BREAK (decimal 243) to the remote host.


          This window type is only available if screen was compiled with the BUILTIN_TELNET option defined.



STRING ESCAPES
       Screen  provides  an  escape mechanism to insert information like the current time into messages or file names.
       The escape character is '%' with one exception: inside of a window's hardstatus '^%' ('^E') is used instead.

       Here is the full list of supported escapes:

       %      the escape character itself

       a      either 'am' or 'pm'

       A      either 'AM' or 'PM'

       c      current time HH:MM in 24h format

       C      current time HH:MM in 12h format

       d      day number

       D      weekday name

       f      flags of the window

       F      sets %? to true if the window has the focus

       h      hardstatus of the window

       H      hostname of the system

       l      current load of the system

       m      month number

       M      month name

       n      window number

       s      seconds

       t      window title

       u      all other users on this window

       w      all window numbers and names. With '-' quailifier: up to the current window; with '+' qualifier:  start-
              ing with the window after the current one.

       W      all window numbers and names except the current one

       y      last two digits of the year number

       Y      full year number

       ?      the  part  to  the  next  '%?'  is displayed only if a '%' escape inside the part expands to a non-empty
              string

       :      else part of '%?'

       =      pad the string to the display's width (like TeX's hfill). If a number is specified, pad to the  percent-
              age  of the window's width.  A '0' qualifier tells screen to treat the number as absolute position.  You
              can specify to pad relative to the last absolute pad position by adding a '+' qualifier or to pad  rela-
              tive  to  the right margin by using '-'. The padding truncates the string if the specified position lies
              before the current position. Add the 'L' qualifier to change this.

       <      same as '%=' but just do truncation, do not fill with spaces

       >      mark the current text position for the next truncation. When screen needs to do truncation, it tries  to
              do  it in a way that the marked position gets moved to the specified percentage of the output area. (The
              area starts from the last absolute pad position and ends with the position specified by  the  truncation
              operator.) The 'L' qualifier tells screen to mark the truncated parts with '...'.

       {      attribute/color modifier string terminated by the next "}"

       '      Substitute  with  the output of a 'backtick' command. The length qualifier is misused to identify one of
              the commands.

       The 'c' and 'C' escape may be qualified with a '0' to make screen use zero instead of space as fill  character.
       The '0' qualifier also makes the '=' escape use absolute positions. The 'n' and '=' escapes understand a length
       qualifier (e.g. '%3n'), 'D' and 'M' can be prefixed with 'L' to generate long names, 'w' and 'W' also show  the
       window flags if 'L' is given.

       An  attribute/color  modifier  is  is  used  to  change  the  attributes  or  the color settings. Its format is
       "[attribute modifier] [color description]". The attribute modifier must be prefixed by a change type  indicator
       if it can be confused with a color desciption. The following change types are known:

       +      add the specified set to the current attributes

       -      remove the set from the current attributes

       !      invert the set in the current attributes

       =      change the current attributes to the specified set

       The attribute set can either be specified as a hexadecimal number or a combination of the following letters:

       d      dim
       u      underline
       b      bold
       r      reverse
       s      standout
       B      blinking

       Colors are coded either as a hexadecimal number or two letters specifying the desired background and foreground
       color (in that order). The following colors are known:

       k      black
       r      red
       g      green
       y      yellow
       b      blue
       m      magenta
       c      cyan
       w      white
       d      default color
       .      leave color unchanged

       The capitalized versions of the letter specify bright colors. You can also use the pseudo-color 'i' to set just
       the brightness and leave the color unchanged.
       A  one  digit/letter  color  description  is treated as foreground or background color dependant on the current
       attributes: if reverse mode is set, the background color is changed instead of the foreground  color.   If  you
       don't like this, prefix the color with a ".". If you want the same behaviour for two-letter color descriptions,
       also prefix them with a ".".
       As a special case, "%{-}" restores the attributes and colors that were set before  the  last  change  was  made
       (i.e. pops one level of the color-change stack).

       Examples:

       "G"    set color to bright green

       "+b r" use bold red

       "= yd" clear all attributes, write in default color on yellow background.

       %-Lw%{= BW}%50>%n%f* %t%{-}%+Lw%<
              The  available  windows centered at the current window and truncated to the available width. The current
              window is displayed white on blue.  This can be used with "hardstatus alwayslastline".

       %?%F%{.R.}%?%3n %t%? [%h]%?
              The window number and title and the window's hardstatus, if one is set.  Also use a  red  background  if
              this is the active focus. Useful for "caption string".

FLOW-CONTROL
       Each  window  has a flow-control setting that determines how screen deals with the XON and XOFF characters (and
       perhaps the interrupt character).  When flow-control is turned off, screen ignores the XON and XOFF characters,
       which  allows  the user to send them to the current program by simply typing them (useful for the emacs editor,
       for instance).  The trade-off is that it will take longer for output  from  a  "normal"  program  to  pause  in
       response  to  an  XOFF.  With flow-control turned on, XON and XOFF characters are used to immediately pause the
       output of the current window.  You can still send these characters to the current program, but you must use the
       appropriate  two-character screen commands (typically "C-a q" (xon) and "C-a s" (xoff)).  The xon/xoff commands
       are also useful for typing C-s and C-q past a terminal that intercepts these characters.

       Each window has an initial flow-control value set with either the -f option or the "defflow" .screenrc command.
       Per  default  the windows are set to automatic flow-switching.  It can then be toggled between the three states
       'fixed on', 'fixed off' and 'automatic' interactively with the "flow" command bound to "C-a f".

       The automatic flow-switching mode deals with flow control using the TIOCPKT mode (like "rlogin" does).  If  the
       tty  driver  does  not support TIOCPKT, screen tries to find out the right mode based on the current setting of
       the application keypad - when it is enabled, flow-control is turned off and visa versa.   Of  course,  you  can
       still manipulate flow-control manually when needed.

       If  you're  running  with  flow-control enabled and find that pressing the interrupt key (usually C-c) does not
       interrupt the display until another 6-8 lines have scrolled by, try running screen with the "interrupt"  option
       (add  the  "interrupt"  flag to the "flow" command in your .screenrc, or use the -i command-line option).  This
       causes the output that screen has accumulated from the interrupted program to be flushed.  One disadvantage  is
       that  the  virtual  terminal's  memory  contains the non-flushed version of the output, which in rare cases can
       cause minor inaccuracies in the output.  For example, if you switch screens and return, or  update  the  screen
       with "C-a l" you would see the version of the output you would have gotten without "interrupt" being on.  Also,
       you might need to turn off flow-control (or use auto-flow mode to turn it off  automatically)  when  running  a
       program that expects you to type the interrupt character as input, as it is possible to interrupt the output of
       the virtual terminal to your physical terminal when flow-control is enabled.  If this happens, a simple refresh
       of  the  screen  with "C-a l" will restore it.  Give each mode a try, and use whichever mode you find more com-
       fortable.



TITLES (naming windows)
       You can customize each window's name in the window display (viewed with the "windows" command (C-a w)) by  set-
       ting  it with one of the title commands.  Normally the name displayed is the actual command name of the program
       created in the window.  However, it is sometimes useful to distinguish various programs of the same name or  to
       change the name on-the-fly to reflect the current state of the window.

       The  default  name  for all shell windows can be set with the "shelltitle" command in the .screenrc file, while
       all other windows are created with a "screen" command and thus can have their name  set  with  the  -t  option.
       Interactively,  there  is  the title-string escape-sequence (<esc>kname<esc>\) and the "title" command (C-a A).
       The former can be output from an application to control the window's name under software control, and the  lat-
       ter will prompt for a name when typed.  You can also bind pre-defined names to keys with the "title" command to
       set things quickly without prompting.

       Finally, screen has a shell-specific heuristic that is enabled by setting the window's  name  to  "search|name"
       and  arranging to have a null title escape-sequence output as a part of your prompt.  The search portion speci-
       fies an end-of-prompt search string, while the name portion specifies the default shell name  for  the  window.
       If  the  name ends in a ':' screen will add what it believes to be the current command running in the window to
       the end of the window's shell name (e.g. "name:cmd").  Otherwise the current command name supersedes the  shell
       name while it is running.

       Here's  how  it works:  you must modify your shell prompt to output a null title-escape-sequence (<esc>k<esc>\)
       as a part of your prompt.  The last part of your prompt must be the same as the string you  specified  for  the
       search  portion of the title.  Once this is set up, screen will use the title-escape-sequence to clear the pre-
       vious command name and get ready for the next command.  Then, when a newline is  received  from  the  shell,  a
       search  is  made for the end of the prompt.  If found, it will grab the first word after the matched string and
       use it as the command name.  If the command name begins with either '!', '%', or '^' screen will use the  first
       word  on  the  following line (if found) in preference to the just-found name.  This helps csh users get better
       command names when using job control or history recall commands.

       Here's some .screenrc examples:

              screen -t top 2 nice top

       Adding this line to your .screenrc would start a nice-d version of the "top" command in window  2  named  "top"
       rather than "nice".

                   shelltitle '> |csh'
                   screen 1

       These  commands would start a shell with the given shelltitle.  The title specified is an auto-title that would
       expect the prompt and the typed command to look something like the following:

              /usr/joe/src/dir> trn

       (it looks after the '> ' for the command name).  The window status would show the name "trn" while the  command
       was running, and revert to "csh" upon completion.

              bind R screen -t '% |root:' su

       Having  this  command  in your .screenrc would bind the key sequence "C-a R" to the "su" command and give it an
       auto-title name of "root:".  For this auto-title to work, the screen could look something like this:

                   % !em
                   emacs file.c

       Here the user typed the csh history command "!em" which ran the previously entered "emacs" command.  The window
       status would show "root:emacs" during the execution of the command, and revert to simply "root:" at its comple-
       tion.

                   bind o title
                   bind E title ""
                   bind u title (unknown)

       The first binding doesn't have any arguments, so it would prompt you for a title. when you type "C-a  o".   The
       second  binding  would  clear an auto-title's current setting (C-a E).  The third binding would set the current
       window's title to "(unknown)" (C-a u).

       One thing to keep in mind when adding a null title-escape-sequence to your prompt is that some shells (like the
       csh) count all the non-control characters as part of the prompt's length.  If these invisible characters aren't
       a multiple of 8 then backspacing over a tab will result in an incorrect display.  One way to get around this is
       to use a prompt like this:

              set prompt='^[[0000m^[k^[\% '

       The  escape-sequence  "<esc>[0000m"  not  only normalizes the character attributes, but all the zeros round the
       length of the invisible characters up to 8.  Bash users will probably want to echo the escape sequence  in  the
       PROMPT_COMMAND:

              PROMPT_COMMAND='echo -n -e "\033k\033\134"'

       (I used "134" to output a '\' because of a bug in bash v1.04).



THE VIRTUAL TERMINAL
       Each  window in a screen session emulates a VT100 terminal, with some extra functions added. The VT100 emulator
       is hard-coded, no other terminal types can be emulated.
       Usually screen tries to emulate as much of the VT100/ANSI standard as possible. But if your terminal lacks cer-
       tain  capabilities,  the emulation may not be complete. In these cases screen has to tell the applications that
       some of the features are missing. This is no problem on machines using termcap,  because  screen  can  use  the
       $TERMCAP variable to customize the standard screen termcap.

       But  if you do a rlogin on another machine or your machine supports only terminfo this method fails. Because of
       this, screen offers a way to deal with these cases.  Here is how it works:

       When screen tries to figure out a terminal name for itself, it first looks for an entry named  "screen.<term>",
       where  <term>  is  the  contents  of  your  $TERM variable.  If no such entry exists, screen tries "screen" (or
       "screen-w" if the terminal is wide (132 cols or more)).  If even this entry cannot be found, "vt100" is used as
       a substitute.

       The  idea  is that if you have a terminal which doesn't support an important feature (e.g. delete char or clear
       to EOS) you can build a new termcap/terminfo entry for screen (named "screen.<dumbterm>") in which  this  capa-
       bility  has  been  disabled.  If this entry is installed on your machines you are able to do a rlogin and still
       keep the correct termcap/terminfo entry.  The terminal name is put in the $TERM variable of  all  new  windows.
       Screen  also  sets  the  $TERMCAP variable reflecting the capabilities of the virtual terminal emulated. Notice
       that, however, on machines using the terminfo database this variable has no effect.  Furthermore, the  variable
       $WINDOW is set to the window number of each window.

       The  actual  set of capabilities supported by the virtual terminal depends on the capabilities supported by the
       physical terminal.  If, for instance, the physical terminal does not support underscore mode, screen  does  not
       put the 'us' and 'ue' capabilities into the window's $TERMCAP variable, accordingly.  However, a minimum number
       of capabilities must be supported by a terminal in order to run screen; namely  scrolling,  clear  screen,  and
       direct  cursor  addressing  (in  addition, screen does not run on hardcopy terminals or on terminals that over-
       strike).

       Also, you can customize the $TERMCAP value used by screen by using  the  "termcap"  .screenrc  command,  or  by
       defining the variable $SCREENCAP prior to startup.  When the is latter defined, its value will be copied verba-
       tim into each window's $TERMCAP variable.  This can either be the full terminal definition, or a filename where
       the terminal "screen" (and/or "screen-w") is defined.

       Note  that  screen honors the "terminfo" .screenrc command if the system uses the terminfo database rather than
       termcap.

       When the boolean 'G0' capability is present in the termcap entry for the terminal  on  which  screen  has  been
       called,  the terminal emulation of screen supports multiple character sets.  This allows an application to make
       use of, for instance, the VT100 graphics character set or national character sets.  The following control func-
       tions from ISO 2022 are supported: lock shift G0 (SI), lock shift G1 (SO), lock shift G2, lock shift G3, single
       shift G2, and single shift G3.  When a virtual terminal is created or reset, the ASCII character set is  desig-
       nated as G0 through G3.  When the 'G0' capability is present, screen evaluates the capabilities 'S0', 'E0', and
       'C0' if present. 'S0' is the sequence the terminal uses to enable and start the graphics character  set  rather
       than  SI.  'E0' is the corresponding replacement for SO. 'C0' gives a character by character translation string
       that is used during semi-graphics mode. This string is built like the 'acsc' terminfo capability.

       When the 'po' and 'pf' capabilities are present in the terminal's termcap  entry,  applications  running  in  a
       screen  window  can send output to the printer port of the terminal.  This allows a user to have an application
       in one window sending output to a printer connected to the terminal, while all other windows are  still  active
       (the  printer port is enabled and disabled again for each chunk of output).  As a side-effect, programs running
       in different windows can send output to the printer simultaneously.  Data sent to the printer is not  displayed
       in the window.  The info command displays a line starting 'PRIN' while the printer is active.

       Screen  maintains  a hardstatus line for every window. If a window gets selected, the display's hardstatus will
       be updated to match the window's hardstatus line. If the display has no hardstatus the line will  be  displayed
       as  a  standard  screen  message.  The hardstatus line can be changed with the ANSI Application Program Command
       (APC): "ESC_<string>ESC\". As a  convenience  for  xterm  users  the  sequence  "ESC]0..2;<string>^G"  is  also
       accepted.

       Some  capabilities  are  only put into the $TERMCAP variable of the virtual terminal if they can be efficiently
       implemented by the physical terminal.  For instance, 'dl' (delete line) is only put into the $TERMCAP  variable
       if  the terminal supports either delete line itself or scrolling regions. Note that this may provoke confusion,
       when the session is reattached on a different terminal, as the value of $TERMCAP cannot be modified  by  parent
       processes.

       The "alternate screen" capability is not enabled by default.  Set the altscreen .screenrc command to enable it.

       The following is a list of control sequences recognized by screen.  "(V)" and "(A)" indicate VT100-specific and
       ANSI- or ISO-specific functions, respectively.


       ESC E                      Next Line

       ESC D                      Index

       ESC M                      Reverse Index

       ESC H                      Horizontal Tab Set

       ESC Z                      Send VT100 Identification String

       ESC 7                 (V)  Save Cursor and Attributes

       ESC 8                 (V)  Restore Cursor and Attributes

       ESC [s                (A)  Save Cursor and Attributes

       ESC [u                (A)  Restore Cursor and Attributes

       ESC c                      Reset to Initial State

       ESC g                      Visual Bell

       ESC Pn p                   Cursor Visibility (97801)

           Pn = 6                 Invisible

                7                 Visible

       ESC =                 (V)  Application Keypad Mode

       ESC >                 (V)  Numeric Keypad Mode

       ESC # 8               (V)  Fill Screen with E's

       ESC \                 (A)  String Terminator

       ESC ^                 (A)  Privacy Message String (Message Line)

       ESC !                      Global Message String (Message Line)

       ESC k                      A.k.a. Definition String

       ESC P                 (A)  Device  Control  String.   Outputs  a  string  directly to the host terminal without
                                  interpretation.

       ESC _                 (A)  Application Program Command (Hardstatus)

       ESC ] 0 ; string ^G   (A)  Operating System Command (Hardstatus, xterm title hack)

       ESC ] 83 ; cmd ^G     (A)  Execute screen command. This only works  if  multi-user  support  is  compiled  into
                                  screen.  The  pseudo-user  ":window:"  is used to check the access control list. Use
                                  "addacl :window: -rwx #?" to create a user with no rights and allow only the  needed
                                  commands.

       Control-N             (A)  Lock Shift G1 (SO)

       Control-O             (A)  Lock Shift G0 (SI)

       ESC n                 (A)  Lock Shift G2

       ESC o                 (A)  Lock Shift G3

       ESC N                 (A)  Single Shift G2

       ESC O                 (A)  Single Shift G3

       ESC ( Pcs             (A)  Designate character set as G0

       ESC ) Pcs             (A)  Designate character set as G1

       ESC * Pcs             (A)  Designate character set as G2

       ESC + Pcs             (A)  Designate character set as G3

       ESC [ Pn ; Pn H            Direct Cursor Addressing

       ESC [ Pn ; Pn f            same as above

       ESC [ Pn J                 Erase in Display

             Pn = None or 0       From Cursor to End of Screen

                  1               From Beginning of Screen to Cursor

                  2               Entire Screen

       ESC [ Pn K                 Erase in Line

             Pn = None or 0       From Cursor to End of Line

                  1               From Beginning of Line to Cursor

                  2               Entire Line

       ESC [ Pn X                 Erase character

       ESC [ Pn A                 Cursor Up

       ESC [ Pn B                 Cursor Down

       ESC [ Pn C                 Cursor Right

       ESC [ Pn D                 Cursor Left

       ESC [ Pn E                 Cursor next line

       ESC [ Pn F                 Cursor previous line

       ESC [ Pn G                 Cursor horizontal position

       ESC [ Pn '                 same as above

       ESC [ Pn d                 Cursor vertical position

       ESC [ Ps ;...; Ps m        Select Graphic Rendition

             Ps = None or 0       Default Rendition

                  1               Bold

                  2          (A)  Faint

                  3          (A)  Standout Mode (ANSI: Italicized)

                  4               Underlined

                  5               Blinking

                  7               Negative Image

                  22         (A)  Normal Intensity

                  23         (A)  Standout Mode off (ANSI: Italicized off)

                  24         (A)  Not Underlined

                  25         (A)  Not Blinking

                  27         (A)  Positive Image

                  30         (A)  Foreground Black

                  31         (A)  Foreground Red

                  32         (A)  Foreground Green

                  33         (A)  Foreground Yellow

                  34         (A)  Foreground Blue

                  35         (A)  Foreground Magenta

                  36         (A)  Foreground Cyan

                  37         (A)  Foreground White

                  39         (A)  Foreground Default

                  40         (A)  Background Black

                  ...

                  49         (A)  Background Default

       ESC [ Pn g                 Tab Clear

             Pn = None or 0       Clear Tab at Current Position

                  3               Clear All Tabs

       ESC [ Pn ; Pn r       (V)  Set Scrolling Region

       ESC [ Pn I            (A)  Horizontal Tab

       ESC [ Pn Z            (A)  Backward Tab

       ESC [ Pn L            (A)  Insert Line

       ESC [ Pn M            (A)  Delete Line

       ESC [ Pn @            (A)  Insert Character

       ESC [ Pn P            (A)  Delete Character

       ESC [ Pn S                 Scroll Scrolling Region Up

       ESC [ Pn T                 Scroll Scrolling Region Down

       ESC [ Pn ^                 same as above

       ESC [ Ps ;...; Ps h        Set Mode

       ESC [ Ps ;...; Ps l        Reset Mode

             Ps = 4          (A)  Insert Mode

                  20         (A)  Automatic Linefeed Mode

                  34              Normal Cursor Visibility

                  ?1         (V)  Application Cursor Keys

                  ?3         (V)  Change Terminal Width to 132 columns

                  ?5         (V)  Reverse Video

                  ?6         (V)  Origin Mode

                  ?7         (V)  Wrap Mode

                  ?9              X10 mouse tracking

                  ?25        (V)  Visible Cursor

                  ?47             Alternate Screen (old xterm code)

                  ?1000      (V)  VT200 mouse tracking

                  ?1047           Alternate Screen (new xterm code)

                  ?1049           Alternate Screen (new xterm code)

       ESC [ 5 i             (A)  Start relay to printer (ANSI Media Copy)

       ESC [ 4 i             (A)  Stop relay to printer (ANSI Media Copy)

       ESC [ 8 ; Ph ; Pw t        Resize the window to 'Ph' lines and 'Pw' columns (SunView special)

       ESC [ c                    Send VT100 Identification String

       ESC [ x                    Send Terminal Parameter Report

       ESC [ > c                  Send VT220 Secondary Device Attributes String

       ESC [ 6 n                  Send Cursor Position Report



INPUT TRANSLATION
       In  order  to  do a full VT100 emulation screen has to detect that a sequence of characters in the input stream
       was generated by a keypress on the user's keyboard and insert the VT100 style escape  sequence.  Screen  has  a
       very flexible way of doing this by making it possible to map arbitrary commands on arbitrary sequences of char-
       acters. For standard VT100 emulation the command will always insert a string in the input buffer of the  window
       (see  also command stuff in the command table).  Because the sequences generated by a keypress can change after
       a reattach from a different terminal type, it is possible to bind commands to the termcap  name  of  the  keys.
       Screen  will insert the correct binding after each reattach. See the bindkey command for further details on the
       syntax and examples.

       Here is the table of the default key bindings. (A) means that the  command  is  executed  if  the  keyboard  is
       switched into application mode.

       Key name          Termcap name    Command
       ______________________________________________________
       Cursor up             ku          stuff \033[A
                                         stuff \033OA    (A)
       Cursor down           kd          stuff \033[B
                                         stuff \033OB    (A)
       Cursor right          kr          stuff \033[C
                                         stuff \033OC    (A)
       Cursor left           kl          stuff \033[D
                                         stuff \033OD    (A)
       Function key 0        k0          stuff \033[10~
       Function key 1        k1          stuff \033OP
       Function key 2        k2          stuff \033OQ
       Function key 3        k3          stuff \033OR
       Function key 4        k4          stuff \033OS
       Function key 5        k5          stuff \033[15~
       Function key 6        k6          stuff \033[17~
       Function key 7        k7          stuff \033[18~
       Function key 8        k8          stuff \033[19~
       Function key 9        k9          stuff \033[20~
       Function key 10       k;          stuff \033[21~
       Function key 11       F1          stuff \033[23~
       Function key 12       F2          stuff \033[24~
       Home                  kh          stuff \033[1~
       End                   kH          stuff \033[4~
       Insert                kI          stuff \033[2~
       Delete                kD          stuff \033[3~
       Page up               kP          stuff \033[5~
       Page down             kN          stuff \033[6~
       Keypad 0              f0          stuff 0
                                         stuff \033Op    (A)
       Keypad 1              f1          stuff 1
                                         stuff \033Oq    (A)
       Keypad 2              f2          stuff 2
                                         stuff \033Or    (A)
       Keypad 3              f3          stuff 3
                                         stuff \033Os    (A)
       Keypad 4              f4          stuff 4
                                         stuff \033Ot    (A)
       Keypad 5              f5          stuff 5
                                         stuff \033Ou    (A)
       Keypad 6              f6          stuff 6
                                         stuff \033Ov    (A)
       Keypad 7              f7          stuff 7
                                         stuff \033Ow    (A)
       Keypad 8              f8          stuff 8
                                         stuff \033Ox    (A)
       Keypad 9              f9          stuff 9
                                         stuff \033Oy    (A)
       Keypad +              f+          stuff +
                                         stuff \033Ok    (A)
       Keypad -              f-          stuff -
                                         stuff \033Om    (A)
       Keypad *              f*          stuff *
                                         stuff \033Oj    (A)
       Keypad /              f/          stuff /
                                         stuff \033Oo    (A)
       Keypad =              fq          stuff =
                                         stuff \033OX    (A)
       Keypad .              f.          stuff .
                                         stuff \033On    (A)
       Keypad ,              f,          stuff ,
                                         stuff \033Ol    (A)
       Keypad enter          fe          stuff \015
                                         stuff \033OM    (A)



SPECIAL TERMINAL CAPABILITIES
       The  following table describes all terminal capabilities that are recognized by screen and are not in the term-
       cap(5) manual.  You can place these capabilities in your termcap entries (in '/etc/termcap') or use  them  with
       the  commands 'termcap', 'terminfo' and 'termcapinfo' in your screenrc files. It is often not possible to place
       these capabilities in the terminfo database.


       LP   (bool)  Terminal has VT100 style margins ('magic margins'). Note that this capability is obsolete  because
                    screen uses the standard 'xn' instead.

       Z0   (str)   Change width to 132 columns.

       Z1   (str)   Change width to 80 columns.

       WS   (str)   Resize  display.  This capability has the desired width and height as arguments. SunView(tm) exam-
                    ple: '\E[8;%d;%dt'.

       NF   (bool)  Terminal doesn't need flow control. Send ^S and ^Q direct to the application. Same as 'flow  off'.
                    The opposite of this capability is 'nx'.

       G0   (bool)  Terminal can deal with ISO 2022 font selection sequences.

       S0   (str)   Switch charset 'G0' to the specified charset. Default is '\E(%.'.

       E0   (str)   Switch charset 'G0' back to standard charset. Default is '\E(B'.

       C0   (str)   Use the string as a conversion table for font '0'. See the 'ac' capability for more details.

       CS   (str)   Switch cursor-keys to application mode.

       CE   (str)   Switch cursor-keys back to normal mode.

       AN   (bool)  Turn on autonuke. See the 'autonuke' command for more details.

       OL   (num)   Set the output buffer limit. See the 'obuflimit' command for more details.

       KJ   (str)   Set the encoding of the terminal. See the 'encoding' command for valid encodings.

       AF   (str)   Change  character  foreground  color in an ANSI conform way. This capability will almost always be
                    set to '\E[3%dm' ('\E[3%p1%dm' on terminfo machines).

       AB   (str)   Same as 'AF', but change background color.

       AX   (bool)  Does understand ANSI set default fg/bg color (\E[39m / \E[49m).

       XC   (str)   Describe a translation of characters to strings depending on the current font. More details follow
                    in the next section.

       XT   (bool)  Terminal understands special xterm sequences (OSC, mouse tracking).

       C8   (bool)  Terminal needs bold to display high-intensity colors (e.g. Eterm).

       TF   (bool)  Add missing capabilities to the termcap/info entry. (Set by default).


CHARACTER TRANSLATION
       Screen  has a powerful mechanism to translate characters to arbitrary strings depending on the current font and
       terminal type.  Use this feature if you want to work with a common standard character set (say  ISO8851-latin1)
       even on terminals that scatter the more unusual characters over several national language font pages.

       Syntax:
           XC=<charset-mapping>{,,<charset-mapping>}
           <charset-mapping> := <designator><template>{,<mapping>}
           <mapping> := <char-to-be-mapped><template-arg>

       The things in braces may be repeated any number of times.

       A  <charset-mapping> tells screen how to map characters in font <designator> ('B': Ascii, 'A': UK, 'K': german,
       etc.)  to strings. Every <mapping> describes to what string a single character will be translated.  A  template
       mechanism  is  used,  as  most of the time the codes have a lot in common (for example strings to switch to and
       from another charset). Each occurrence of '%' in <template> gets substituted with the <template-arg>  specified
       together  with  the character. If your strings are not similar at all, then use '%' as a template and place the
       full string in <template-arg>. A quoting mechanism was added to make it possible to use a  real  '%'.  The  '\'
       character quotes the special characters '\', '%', and ','.

       Here is an example:

           termcap hp700 'XC=B\E(K%\E(B,\304[,\326\\\\,\334]'

       This  tells  screen  how  to translate ISOlatin1 (charset 'B') upper case umlaut characters on a hp700 terminal
       that has a german charset. '\304' gets translated to '\E(K[\E(B' and so on.  Note that this  line  gets  parsed
       *three*  times before the internal lookup table is built, therefore a lot of quoting is needed to create a sin-
       gle '\'.

       Another extension was added to allow more emulation: If a mapping translates the unquoted '%' char, it will  be
       sent  to the terminal whenever screen switches to the corresponding <designator>. In this special case the tem-
       plate is assumed to be just '%' because the charset switch sequence and the character mappings normally haven't
       much in common.

       This example shows one use of the extension:

           termcap xterm 'XC=K%,%\E(B,[\304,\\\\\326,]\334'

       Here,  a part of the german ('K') charset is emulated on an xterm.  If screen has to change to the 'K' charset,
       '\E(B' will be sent to the terminal, i.e. the ASCII charset is used instead. The template is just '%',  so  the
       mapping is straightforward: '[' to '\304', '\' to '\326', and ']' to '\334'.


ENVIRONMENT
       COLUMNS        Number of columns on the terminal (overrides termcap entry).
       HOME           Directory in which to look for .screenrc.
       LINES          Number of lines on the terminal (overrides termcap entry).
       LOCKPRG        Screen lock program.
       NETHACKOPTIONS Turns on nethack option.
       PATH           Used for locating programs to run.
       SCREENCAP      For customizing a terminal's TERMCAP value.
       SCREENDIR      Alternate socket directory.
       SCREENRC       Alternate user screenrc file.
       SHELL          Default shell program for opening windows (default "/bin/sh").
       STY            Alternate socket name.
       SYSSCREENRC    Alternate system screenrc file.
       TERM           Terminal name.
       TERMCAP        Terminal description.
       WINDOW         Window number of a window (at creation time).

FILES
       .../screen-4.?.??/etc/screenrc
       .../screen-4.?.??/etc/etcscreenrc Examples  in  the screen distribution package for private and global initial-
                                         ization files.
       $SYSSCREENRC
       /etc/screenrc                     screen initialization commands
       $SCREENRC
       $HOME/.screenrc                   Read in after /etc/screenrc
       $SCREENDIR/S-<login>
       /local/screens/S-<login>          Socket directories (default)
       /usr/tmp/screens/S-<login>        Alternate socket directories.
       <socket directory>/.termcap       Written by the "termcap" output function
       /usr/tmp/screens/screen-exchange  or
       /tmp/screen-exchange              screen 'interprocess communication buffer'
       hardcopy.[0-9]                    Screen images created by the hardcopy function
       screenlog.[0-9]                   Output log files created by the log function
       /usr/lib/terminfo/?/*             or
       /etc/termcap                      Terminal capability databases
       /etc/utmp                         Login records
       $LOCKPRG                          Program that locks a terminal.


SEE ALSO
       termcap(5), utmp(5), vi(1), captoinfo(1), tic(1)


AUTHORS
       Originally created by Oliver Laumann, this latest version was produced by Wayne Davison,  Juergen  Weigert  and
       Michael Schroeder.

COPYLEFT
       Copyright (C) 1993-2003
            Juergen Weigert (jnweigerATimmd4.de)
            Michael Schroeder (mlschroeATimmd4.de)
       Copyright (C) 1987 Oliver Laumann
       This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Pub-
       lic License as published by the Free Software Foundation; either version 2, or (at your option) any later  ver-
       sion.
       This  program  is  distributed  in  the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the
       implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU  General  Public  License
       for more details.
       You  should  have received a copy of the GNU General Public License along with this program (see the file COPY-
       ING); if not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
       USA

CONTRIBUTORS
       Ken Beal (kbealATamber.com),
       Rudolf Koenig (rfkoenigATimmd4.de),
       Toerless Eckert (eckertATimmd4.de),
       Wayne Davison (davisonATborland.com),
       Patrick Wolfe (patATkai.com, kailand!pat),
       Bart Schaefer (schaeferATcse.edu),
       Nathan Glasser (nathanATbrokaw.edu),
       Larry W. Virden (lvirdenATcas.org),
       Howard Chu (hycAThanauma.gov),
       Tim MacKenzie (tymATdibbler.au),
       Markku Jarvinen (mta@{cc,cs,ee}.tut.fi),
       Marc Boucher (marcATCAM.ORG),
       Doug Siebert (dsiebertATisca.edu),
       Ken Stillson (stillsonATtsfsrv.org),
       Ian Frechett (frechettATspot.EDU),
       Brian Koehmstedt (bpkATgnu.edu),
       Don Smith (djs6015ATultb.edu),
       Frank van der Linden (vdlindenATfwi.nl),
       Martin Schweikert (schweikATcpp.de),
       David Vrona (daveATsashimi.com),
       E. Tye McQueen (tye%spillman.UUCPATuunet.net),
       Matthew Green (mrgATeterna.au),
       Christopher Williams (cgwATpobox.com),
       Matt Mosley (mattmATaccess.net),
       Gregory Neil Shapiro (gshapiroATwpi.EDU),
       Johannes Zellner (johannesATzellner.org),
       Pablo Averbuj (pabloATaverbuj.com).


VERSION
       This  is  version 4.0.2. Its roots are a merge of a custom version 2.3PR7 by Wayne Davison and several enhance-
       ments to Oliver Laumann's version 2.0. Note that all versions numbered 2.x are copyright by Oliver Laumann.

AVAILABILITY
       The latest official release of screen available via anonymous ftp from  gnudist.gnu.org,  nic.funet.fi  or  any
       other  GNU  distribution  site.  The  home  site  of screen is ftp.uni-erlangen.de, in the directory pub/utili-
       ties/screen. The subdirectory 'private' contains the latest beta testing release. If you want to help,  send  a
       note to screenATuni-erlangen.de.

BUGS
       ?  'dm'  (delete mode) and 'xs' are not handled correctly (they are ignored). 'xn' is treated as a magic-margin
          indicator.

       ?  Screen has no clue about double-high or double-wide characters.  But this is the only area where  vttest  is
          allowed to fail.

       ?  It  is  not possible to change the environment variable $TERMCAP when reattaching under a different terminal
          type.

       ?  The support of terminfo based systems is very limited. Adding extra capabilities to $TERMCAP  may  not  have
          any effects.

       ?  Screen does not make use of hardware tabs.

       ?  Screen  must be installed as set-uid with owner root on most systems in order to be able to correctly change
          the owner of the tty device file for each window.  Special permission may also be required to write the file
          "/etc/utmp".

       ?  Entries  in  "/etc/utmp"  are not removed when screen is killed with SIGKILL.  This will cause some programs
          (like "w" or "rwho") to advertise that a user is logged on who really isn't.

       ?  Screen may give a strange warning when your tty has no utmp entry.

       ?  When the modem line was hung up, screen may not automatically detach (or quit) unless the device  driver  is
          configured to send a HANGUP signal.  To detach a screen session use the -D or -d command line option.

       ?  If a password is set, the command line options -d and -D still detach a session without asking.

       ?  Both  "breaktype"  and  "defbreaktype"  change the break generating method used by all terminal devices. The
          first should change a window specific setting, where the latter should change only the default for new  win-
          dows.

       ?  When  attaching  to a multiuser session, the user's .screenrc file is not sourced. Each user's personal set-
          tings have to be included in the .screenrc file from which the session is booted, or have to be changed man-
          ually.

       ?  A weird imagination is most useful to gain full advantage of all the features.

       ?  Send bug-reports, fixes, enhancements, t-shirts, money, beer & pizza to screenATuni-erlangen.de.




4th Berkeley Distribution          Aug 2003                          SCREEN(1)