After setting the external port configuration, type exit twice to back out of the configuration mode of the command line.
在设置外部端口配置之后，输入exit两次，退出命令行的配置模式。
2
This would normally be done by setting the Emacs variable sgml-validate-command, and in fact we will set this variable to handle the case of using OpenSp's onsgmls executable to validate in sgml-mode.