tclsh(1)                 Tcl Applications                tclsh(1)



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NAME
       tclsh - Simple shell containing Tcl interpreter

SYNOPSIS
       tclsh ?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 com-
       mand  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, 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 argument
       is the name of a script file and 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 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 com-
       mand 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's  installed  somewhere  else  then
       you'll  have to modify the above line to match.  Many UNIX
       systems do not allow the #! line to exceed about 30  char-
       acters 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  doesn't 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 previ-
       ous approach.  Third, this  approach  will  work  even  if
       tclsh  is itself a shell script (this is done on some sys-
       tems in order to handle multiple architectures or  operat-
       ing  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 practise 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  disadvan- |
       tage  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 argu-
                      ments  (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  interac-
                      tively (no fileName was specified and stan-
                      dard 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  vari-
       able  tcl_prompt2  is used in a similar way when a newline
       is typed but the current command isn't  yet  complete;  if
       tcl_prompt2  isn't set then no prompt is output for incom-
       plete commands.


STANDARD CHANNELS
       See Tcl_StandardChannels for more explanations.


SEE ALSO
       fconfigure(n), tclvars(n)


KEYWORDS
       argument, interpreter, prompt, script file, shell



Tcl                                                      tclsh(1)