debian man page for tclsh

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 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, "32" ("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 "32", "x1a", or "u001a"; or may generate it by use of commands such as for-
       mat 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 "$0" "$@"
       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 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  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.

SEE ALSO
       encoding(n), fconfigure(n), tclvars(n)

KEYWORDS
       argument, interpreter, prompt, script file, shell

Tcl                                                                                                                                       tclsh(1)