-c：取消前一次關(guān)機(jī)命令-h：關(guān)機(jī)-r：重啟 

[root@localhost tmp]# dateSat Jul 15 09:28:35 CST 2017[root@localhost tmp]# shutdown -r 05:30Shutdown scheduled for Sun 2017-07-16 05:30:00 CST, use 'shutdown -c' to cancel.[root@localhost tmp]# shutdown -r 05:30 &[1] 4936[root@localhost tmp]# Shutdown scheduled for Sun 2017-07-16 05:30:00 CST, use 'shutdown -c' to cancel. Broadcast message from root@localhost.localdomain (Sat 2017-07-15 09:30:00 CST): The system is going down for reboot at Sun 2017-07-16 05:30:00 CST! ^C[1]+ Done shutdown -r 05:30[root@localhost tmp]# shutdown -c Broadcast message from root@localhost.localdomain (Sat 2017-07-15 09:31:03 CST): The system shutdown has been cancelled at Sat 2017-07-15 09:32:03 CST!

haltinit 0poweroff 

rebootinit 6 

runlevelcat /etc/inittab

logout

[root@localhost tmp]# [root@localhost tmp]# runlevelN 5[root@localhost tmp]# init 3PolicyKit daemon disconnected from the bus.We are no longer a registered authentication agent.[root@localhost tmp]# runlevel5 3[root@localhost tmp]# logout