systemctl start postfix.service关闭一个服务：systemctl stop postfix.service重启一个服务：systemctl restart postfix.service显示一个服务的状态：systemctl status postfix.service在开机时启用一个服务：systemctl enable postfix.service在开机时禁用一个服务：systemctl disable postfix.service查看服务是否开机启动：systemctl is-enabled postfix.service查看已启动的服务列表：systemctl list-unit-files|grep enabled查看启动失败的服务列表：systemctl --failed新闻热点
疑难解答
