centos systemctl指令

# systemctl				#输出已激活单元

# systemctl list-units		#输出已激活单元

# systemctl --failed			#输出运行失败的单元

# systemctl list-unit-files		#查看所有已安装服务

# systemctl start nginx		#启动nginx

# systemctl stop nginx		#停止nginx

# systemctl restart nginx		#重启nginx

# systemctl reload nginx		#重新加载nginx配置

# systemctl status nginx		#输出nginx运行状态

# systemctl is-enabled nginx	#检查nginx是否配置为自动启动

# systemctl enable nginx		#开机自动启动nginx

# systemctl disable nginx		#取消开机自动启动nginx

# systemctl help nginx		#显示nginx的手册页

# systemctl daemon-reload		#重新载入 systemd，扫描新的或有变动的单元

# systemctl reboot			#重启

# systemctl poweroff			#退出系统并停止电源

# systemctl suspend			#待机

# systemctl hibernate		#休眠

# systemctl hybrid-sleep		#混合休眠模式（同时休眠到硬盘并待机

# systemctl isolate graphical.target	#等价于telinit 3 或 telinit 5