def which(self,mess,args):
     ''' UNIX which command '''
     path=SystemUtils.which(args)
     if path:
         return "%s : %s" % (args,path)
     else:
         return "%s : command not found" % args
 def unknown_command(self, mess, cmd, args):
     path=SystemUtils.which(cmd)
     if path is not None:
         return self.__sysu.execmd(str(mess.getBody()))
     else:
         return None