1. power management:

        shutdown:

        

-h: Equivalent to --poweroff, overridden by --halt

-r --reboot    Reboot the machine

-c: Cancel a pending shutdown


时间格式

now

+m

hh:mm


        reboot, halt, poweroff - reboot or stop the system

                

                -f, --force:Does not invoke shutdown(8) and instead performs the actual action you would expect from the name