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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 ...?
____________________________________________________________________________________________________________


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, interac-tive interactive
       tive 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, optionally, 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 commands 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  appli-cation application
       cation will read text up to but not including the character.  An application that requires this char-acter character
       acter 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/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/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 architectures or operating systems:  the tclsh script selects one of sev-eral several
       eral 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 com-ments, comments,
       ments, 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 evalu-ate evaluate
       ate  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)