tcl ?-qn? ?-f? script?|?-c command? ?args?

       Tcl  starts  the interactive Tcl command interpreter.  The
       Tcl shell provides an environment for  writing,  debugging
       and  executing  Tcl scripts.  The functionality of the Tcl
       shell can be  easily  obtained  by  any  application  that
       includes Tcl.

       The  tcl command, issued without any arguments, invokes an
       interactive Tcl  shell,  allowing  the  user  to  interact
       directly  with Tcl, executing any Tcl commands at will and
       viewing their results.

       If script is specified, then the script is  executed  non-
       interactively  with  any additional arguments, args, being
       supplied in the global Tcl variable `argv'.  If command is
       supplied, then this command (or semicolon-separated series
       of commands) is executed, with `argv' containing any args.

       The  Tcl  shell is intended as an environment for Tcl pro-
       gram development and execution.  While it is not  a  full-
       featured  interactive  shell,  it  provides  a comfortable
       environment for the interactive development of  Tcl  code.
       Note  that  the  package library code described here over-
       rides the unknown command provided as part of the standard
       Berkeley   Tcl   library  facility,  although  Tcl  source
       libraries coded to that standard can be loaded and used by
       Extended Tcl.

       The following command line flags are recognized by the Tcl
       shell command line parser:

       -q     Quick initialization flag.  The  Tcl  initiaization
              file is not evaluated and the auto_path variable is
              not set.   Tcl  auto-load  libraries  will  not  be
              available.

       -n     No  procedure  call stack dump.  The procedure call
              stack will not be displayed when an  error  occurs,
              only  the  error message.  Useful in the #! line of
              already debugged scripts.

       -f     Takes the next argument as  a  script  for  Tcl  to
              source, rather than entering interactive mode.  The
              -f flag is optional.  Normally the  first  argument
              that  does  not  start  with  a `-' is taken as the
              script to execute unless the `-c' option is  speci-
              fied.   Any  following  arguments are passed to the
              script via argv, thus any other Tcl shell  command-
              line flags must precede this option.

       -c     Take the next argument as a Tcl command to execute.
              It may contain series of commands to execute, sepa-
              rated  by  `;'.  Any following arguments are passed
              in argv, thus, as with  -f,  any  other  Tcl  shell
              flags must precede this option.

       --     Mark the end of the arguments to the Tcl shell. All
              arguments following this  are  passed  in  the  Tcl
              variable  argv.   This  is useful to pass arguments
              without attempting to execute a Tcl script.

       The result string returned by a command executed from  the
       Tcl  shell  command  line  is  normally echoed back to the
       user.  If an error occurs, then the string result is  dis-
       played,  along  with the error message.  The error message
       will be preceded by the string ``Error:''.

       The set command is a special  case.   If  the  command  is
       called  to  set a variable (i.e. with two arguments), then
       the result will not be echoed.  If only one argument,  the
       name  of  a  variable, is supplied to set, then the result
       will be echoed.

       If an unknown Tcl command  is  entered  from  the  command
       line,  then  the Unix command path, specified in the envi-
       ronment variable PATH, will be searched for a  command  of
       the  same  name.  If the command is found, it will be exe-
       cuted with any arguments remaining on the Tcl command line
       being passed as arguments to the command.  This feature is
       provided to enhance the interactive environment for devel-
       oping Tcl scripts.

       Automatic  execution  of  programs  in this manner is only
       supported from the command line, not in script files or in
       procedures,  to  reduce  confusion and mistakes while pro-
       gramming in Tcl.  Scripts should use the Tcl exec or  sys-
       tem commands to run Unix commands.

       This functionallity is provided by Extended Tcl.