def cmd_rnto(param)
      send_unauthorised and return unless logged_in?
      send_param_required and return if param.nil?

      @driver.rename(@from_filename, build_path(param)) do |result|
        if result
          send_response "250 File renamed."
        else
          send_action_not_taken
        end
      end
    end
def cmd_rnto(param)
      send_unauthorised and return unless logged_in?
      send_param_required and return if param.nil?

      @driver.rename(@from_filename, build_path(param)) do |result|
        if result
          send_response "250 File renamed."
        else
          send_action_not_taken
        end
      end
    end
rename a file