       1mcommandloop  22m?1m-async22m?  ?1m-interactive  on  |  off  | tty22m? ?1m-prompt1 4m22mcmd24m?
       ?1m-prompt2 4m22mcmd24m? ?1m-endcommand 4m22mcmd24m?

              Create  an  interactive command loop reading commands from stdin
              and writing results to stdout.  Command loops are  maybe  either
              be  blocking  or event oriented.  This command is useful for Tcl
              scripts that do not normally converse interactively with a  user
              through  a  Tcl command interpreter, but which sometimes want to
              enter this mode, perhaps for debugging  or  user  configuration.
              The command loop terminates on EOF.

              The following options are available:

              1m-async 22mA  command  handler  will be associated with stdin.  When
                     input is available on stdin, it will be read and  accumu-
                     lated  until  a  full command is available.  That command
                     will then be evaluated.  An event loop  must  be  entered
                     for input to be read and processed.

              1m-interactive on | off | tty0m
                     Enable  or disable interactive command mode.  In interac-
                     tive mode, commands are prompted for and the  results  of
                     comments  are printed.  The value maybe any boolean value
                     or 1mtty22m.  If 1mtty 22mis used, interactive mode is  enabled  if
                     stdin is associated with a terminal or terminal emulator.
                     The default is 1mtty22m.

              1m-prompt1 4m22mcmd0m
                     If specified, 4mcmd24m  is used is  evaluate  and  its  result
                     used  for the main command prompt.  If not specified, the
                     command in 1mtcl_prompt1 22mis evaluated to output the prompt.
                     Note  the  difference  in  behavior, 4mcmd24m results is used,
                     while 1mtcl_prompt1 22moutputs.  This is to allow  for  future
                     expansion  to command loops that write to other than std-
                     out.

              1m-prompt2 4m22mcmd0m
                     If specified, 4mcmd24m is used is evaluate and its result used
                     for  the secondary (continuation) command prompt.  If not
                     specified, the command in  1mtcl_prompt2  22mis  evaluated  to
                     output the prompt.

              1m-endcommand 4m22mcmd0m
                     If specified, 4mcmd24m is evaluated when the command loop ter-
                     minates.

                     In interactive mode, the results of set commands with two
                     arguments are not printed.

                     If  1mSIGINT  22mis configured to generate a Tcl error, it can
                     be used to delete the current command being type  without
                     aborting the program in progress.
