[root@localhost tmp]# date
sat jul 15 09:28:35 cst 2017
[root@localhost tmp]# shutdown -r 05:30
shutdown 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!