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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 stan-
       dard 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, ("\x1A", control-Z).  If this character is present
       in the file, the	tclsh application will read text up to but not includ-
       ing  the	character.  An application that	requires this character	in the
       file may	safely encode it as "\x1A"; or may generate it by use of  com-
       mands  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  in-
       stalled	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 charac-
       ters 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 follow-
       ing 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 it-
       self  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 al-
       lowing 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.

       Alternatively, you can use /usr/bin/env to locate tclsh	on  the	 path,
       like this:

	      #!/usr/bin/env tclsh

       That has	the advantages of being	succinct and simple, but the disadvan-
       tage of not being flexible in the face of varying names for the binary.

VARIABLES
       Tclsh sets the following	global Tcl variables in	addition to those cre-
       ated  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 argu-
		      ments, in	order, or an empty string if there are no  arg
		      arguments.

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

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

PROMPTS
       When  tclsh  is invoked interactively it	normally prompts for each com-
       mand with "% ".	You can	change the prompt by setting the global	 vari-
       ables tcl_prompt1 and tcl_prompt2.  If variable tcl_prompt1 exists then
       it  must	 consist  of a Tcl script to output a prompt;  instead of out-
       putting 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.

ZIPFS VIRTUAL FILE SYSTEM
       When  a	zipfile	 is concatenated to the	end of a tclsh,	on startup the
       contents	of the zip archive will	be mounted under a virtual file	system
       (VFS). The root of that VFS can be retrieved using the zipfs root  com-
       mand.  The  zip	archive	 is mounted under the app directory within the
       VFS. If a file named main.tcl is	present	in the top level directory  of
       the  zip	 archive, it will be sourced instead of	tclsh's	normal command
       line handing. If	a top level directory tcl_library is  present  in  the
       zip  archive,  it will become the directory loaded as env(TCL_LIBRARY).
       If a file named main.tcl	is present in the top level directory  of  the
       zip  archive,  it will be sourced instead of the	shell's	normal command
       line handling.

       Only one	zipfile	can be concatenated to the  end	 of  executable	 image
       (tclsh,	or wish). However, if multiple zipfiles	are concatenated, only
       the last	one is used.

       This filesystem is read-only. Files cannot be added or modified	within
       this mounted file system.  See zipfs(n) for complete details.

SEE ALSO
       auto_path(n), encoding(n), env(n), fconfigure(n), zipfs(n)

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

Tcl								      tclsh(1)

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