systemctl enable httpd.service     #使某服务自动启动

systemctl disable httpd.service    #使某服务不自动启动

systemctl status httpd.service     #服务详细信息

systemctl is-active httpd.service   #仅显示是否Active

systemctl list-units--type=service  #显示所有已启动的服务

systemctl start httpd.service     #启动某项服务

systemctl stop httpd.service     #停止某项服务

systemctl restart httpd.service  #重启某项服务

systemctl命令的使用方法