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Tcl

summary

    This subchapter looks at tcl, a Unix (and Linux) command, including both running shell scripts from a web browser and running Tcl from the shell.

    tcl is used to run a CLI version of Tcl.

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Tcl

    This subchapter looks at tcl, a Unix (and Linux) command, including both running shell scripts from a web browser and running Tcl from the shell.

    tcl is used to run a CLI version of Tcl.

getting started

    Use which to determine the location of your local copy of Tcl (and to make sure you actually have a copy):

    $ which tclsh
    /usr/bin/tclsh
    $

    This example assumes that you have created the scripts directory in your home directory.

    Create a tcl script called script.tcl and save it in the new scripts directory (folder):

    #!/usr/bin/tclsh
    puts "Hello World!"

    Run your new script by running the tclsh program with your script as the file to execute:

    $ tclsh ~/scripts/script.tcl
    Hello World!
    $

text-based interactive version

    To run a text-only version of tclsh, simply type tclsh (and return) from the BASH command line and you should get a percent sign (%) prompt. This means you have sccessfully entered tclsh.

    $ tclsh
    %

    Now that you are in tclsh, type info tclversion to see which version.

    % info tclversion
    8.5
    %

    And to see Tcl make use of a simple BASH command, type ls -l:

    % ls -l
    a regular listing of files
    %

    And to return back to BASH, type exit:

    % exit
    $

visual interactive version

    Now test out the visual version by typing wish (assuming it is installed and you have X-Windows running).

    $ wish
    %

    The contents of your Terminal window will not change from the text-only version, but you will get an additional display window that is controlled from the command line.

    And return to BASH:

    % exit
    $

brief history

    Tcl was created in the late 1980s by Dr. John Osterhout. Tcl stands for Tool Command Language.

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