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tclsh(1)                       Tcl Applications                       tclsh(1)



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NAME
       tclsh - Simple shell containing Tcl interpreter

SYNOPSIS
       tclsh ?-encoding name? ?fileName arg arg ...?
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DESCRIPTION
       Tclsh  is a shell-like application that reads Tcl commands from its standard input or from a file and evaluates
       them.  If invoked with no arguments then it runs interactively, reading Tcl commands from  standard  input  and
       printing  command  results and error messages to standard output.  It runs until the exit command is invoked or
       until it reaches end-of-file on its standard input.  If there exists a file .tclshrc  (or  tclshrc.tcl  on  the
       Windows platforms) in the home directory of the user, interactive tclsh evaluates the file as a Tcl script just
       before reading the first command from standard input.


SCRIPT FILES
       If tclsh is invoked with arguments then the first few arguments specify the name of a script file, and, option- |
       ally, the encoding of the text data stored in that script file.  Any additional arguments are made available to
       the script as variables (see below).  Instead of reading commands from standard input tclsh will read Tcl  com-
       mands  from  the  named file;  tclsh will exit when it reaches the end of the file.  The end of the file may be
       marked either by the physical end of the medium, or by the character, "\032" ("\u001a",  control-Z).   If  this
       character  is  present in the file, the tclsh application will read text up to but not including the character.
       An application that requires this character in the file may safely encode it as "\032", "\x1a", or "\u001a"; or
       may generate it by use of commands such as format or binary.  There is no automatic evaluation of .tclshrc when
       the name of a script file is presented on the tclsh command line, but the script file can always source  it  if
       desired.

       If you create a Tcl script in a file whose first line is
              #!/usr/local/bin/tclsh
       then  you can invoke the script file directly from your shell if you mark the file as executable.  This assumes
       that tclsh has been installed in the default location in /usr/local/bin;  if it  is  installed  somewhere  else
       then  you  will  have  to modify the above line to match.  Many UNIX systems do not allow the #! line to exceed
       about 30 characters in length, so be sure that the tclsh executable can be accessed with a short file name.

       An even better approach is to start your script files with the following three lines:
              #!/bin/sh
              # the next line restarts using tclsh \
              exec tclsh "$0" "$@"
       This approach has three advantages over the approach in the previous paragraph.  First,  the  location  of  the
       tclsh  binary  does  not  have to be hard-wired into the script:  it can be anywhere in your shell search path.
       Second, it gets around the 30-character file name limit in the previous approach.  Third,  this  approach  will
       work even if tclsh is itself a shell script (this is done on some systems in order to handle multiple architec-
       tures or operating systems:  the tclsh script selects one of several binaries to run).  The three  lines  cause
       both  sh  and tclsh to process the script, but the exec is only executed by sh.  sh processes the script first;
       it treats the second line as a comment and executes the third line.  The exec statement cause the shell to stop
       processing  and  instead to start up tclsh to reprocess the entire script.  When tclsh starts up, it treats all
       three lines as comments, since the backslash at the end of the second line causes the third line to be  treated
       as part of the comment on the second line.

       You  should  note that it is also common practice to install tclsh with its version number as part of the name.
       This has the advantage of allowing multiple versions of Tcl to exist on the same system at once, but  also  the
       disadvantage of making it harder to write scripts that start up uniformly across different versions of Tcl.


VARIABLES
       Tclsh sets the following Tcl variables:

       argc           Contains  a  count  of  the  number  of arg arguments (0 if none), not including the name of the
                      script file.

       argv           Contains a Tcl list whose elements are the arg arguments, in order, or an empty string if  there
                      are no arg arguments.

       argv0          Contains fileName if it was specified.  Otherwise, contains the name by which tclsh was invoked.

       tcl_interactive
                      Contains 1 if tclsh is running interactively (no fileName was specified and standard input is  a
                      terminal-like device), 0 otherwise.


PROMPTS
       When  tclsh is invoked interactively it normally prompts for each command with "% ".  You can change the prompt
       by setting the variables tcl_prompt1 and tcl_prompt2.  If variable tcl_prompt1 exists then it must consist of a
       Tcl  script  to output a prompt;  instead of outputting a prompt tclsh will evaluate the script in tcl_prompt1.
       The variable tcl_prompt2 is used in a similar way when a newline is typed but the current command  is  not  yet
       complete; if tcl_prompt2 is not set then no prompt is output for incomplete commands.


STANDARD CHANNELS
       See Tcl_StandardChannels for more explanations.


SEE ALSO
       encoding(n), fconfigure(n), tclvars(n)


KEYWORDS
       argument, interpreter, prompt, script file, shell



Tcl                                                                   tclsh(1)