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, “\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(n), encoding(n), env(n), fconfigure(n)

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



Tcl                                                                   tclsh(1)