       The following variables are set and/or used by the Tcl shell.

       argv0  Contains  the  name  of the Tcl program specified on the command
              line or the name that the Tcl shell was invoked under if no pro-
              gram was specified.  argc Contains a count of the number of argv
              arguments (0 if none).  argv A  list  containing  the  arguments
              passed in from the command line, excluding arguments used by the
              Tcl shell.  The first element is the first passed argument,  not
              the program name.

       tcl_interactive
              Set  to 1 if Tcl shell is invoked interactively, or 0 if the Tcl
              shell is directly  executing  a  script.   Normally  checked  by
              scripts so that they can function as a standalone application if
              specified on the command line, but merely load in and  not  exe-
              cute if loaded during an interactive invocation of Tcl.

       auto_path
              Path  to  search  to locate Tcl autoload libraries.  Used by the
              both the Tcl and TclX library autoloading facility.

       tclx_library
              Path to the TclX runtime library.   If  your  running  the  TclX
              shell or an application based on it (like wishx).  The TclX ini-
              tialization file normally adds this to the auto_path.

       tkx_library
              Path to the TkX runtime library.   This  is  set  only  if  your
              application  has  called  Tkx_Init.  The TkX initialization file
              normally adds this to the auto_path.

       tcl_prompt1
              Contains code to run to output the  prompt  used  when  interac-
              tively prompting for commands.

       tcl_prompt2
              Contains  code  to  run  to output the prompt used when interac-
              tively prompting for continuation of an incomplete command.

       TCLXENV
              Array that contains information used internally by  various  Tcl
              procedures  that  are part of the TclX shell.  Don't change this
