shutdown  系统关机

[root@Supreme ~]# shutdown
Shutdown scheduled for Thu 2020-05-21 14:03:15 CST, use ‘shutdown -c‘ to cancel.
[root@Supreme ~]#        定义一个关机时间                    取消关机计划
Broadcast message from root@Supreme (Thu 2020-05-21 14:02:15 CST):
 会将关机信息广播给所有关机的用户
The system is going down for power-off at Thu 2020-05-21 14:03:15 CST!
准备什么时间真正的关机

stutdown - c    取消关机
[root@Supreme ~]# shutdown -c 
Broadcast message from root@Supreme (Thu 2020-05-21 14:15:14 CST): Permission  denied  权限阻止
The system shutdown has been cancelled at Thu 2020-05-21 14:16:14 CST!

shutdown -r now    关机后重启
shutdown -h now    关机后不重启
shutdown -r +10    10分钟后重启
shutdown -r 10:00  10点钟重启
shutdown -h +10    10分钟后关机
shutdown -h 10:00  10点钟关机

reboot   直接重启
halt     直接关机