code: def shlex_process_stdin(process_command, helptext):
      
      # if input is interactive, print help to stderr
      if sys.stdin.isatty():
          safeprint(
              (
                  "{}\n".format(helptext) + "Lines are split with shlex in POSIX mode: "
                  "https://docs.python.org/library/shlex.html#parsing-rules\n"
                  "Terminate input with Ctrl+D or <EOF>\n"
              ),
              write_to_stderr=True,
          )
  
      # use readlines() rather than implicit file read line looping to force
      # python to properly capture EOF (otherwise, EOF acts as a flush and
      # things get weird)
      for line in sys.stdin.readlines():
          # get the argument vector:
          # do a shlex split to handle quoted paths with spaces in them
          # also lets us have comments with #
          argv = shlex.split(line, comments=True)
          if argv:
              try:
                  process_command.main(args=argv)
              except SystemExit as e:
                  if e.code != 0:
                      raise
docs: Use shlex to process stdin line-by-line.
      Also prints help text.
  
      Requires that @process_command be a Click command object, used for
      processing single lines of input. helptext is prepended to the standard
      message printed to interactive sessions.