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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, read-
       ing  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 Win-
       dows 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 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 exe-
       cutable.  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  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 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 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 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 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 isn't
       yet complete; if tcl_prompt2 isn't set then no prompt is output for incomplete 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)
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