code: def do_file(self, line):
          
          opts = self.FILE_OPTS
  
          if not self.all_ontologies:
              self._help_nofiles()
              return
  
          line = line.split()
  
          if not line or line[0] not in opts:
              self.help_file()
              return
  
          if line[0] == "rename":
              self._rename_file()
          elif line[0] == "delete":
              self._delete_file()
          else:
              return
docs: PErform some file operation