Shutdown
From FreeBSDwiki
Used to shutdown a machine. shutdown requires two arguments: a command and a time.
Common Flags and arguments
-h will halt the machine -r will reboot the machine -k will send out a message that the machine will reboot, but not actually do it now is a valid time
shudown -h now will halt the machine immediately; all pending writes performed, all disks sync'd and all users will be logged out
Compare to init