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, 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 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" ${1+"$@"}

       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 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 global Tcl variables in addition to  those  created  by  the  Tcl
       library itself (such as env, which maps environment variables such as PATH into Tcl):

       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 global 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

       auto_path(3tcl), encoding(3tcl), env(3tcl), fconfigure(3tcl)

KEYWORDS

       application, argument, interpreter, prompt, script file, shell