code: def preloop(self):
          
          cmd.Cmd.preloop(self)   ## sets up command completion
  
          try:
              if readline:
                  readline.read_history_file(sys.argv[0] + ".history")
          except Exception, err:
              if not isinstance(err, IOError):
                  self.stdout.write("history error: %s\n" % err)
docs: Initialization before prompting user for commands.
          Despite the claims in the Cmd documentaion, Cmd.preloop() is not a stub.