How to shutdown or reboot a Unix machine

Shutdown
the program is usually in /sbin


 * execute
 * /etc/halt
 * for a shutdown but not necessarily powerdown
 * /etc/halt -p
 * for shutdown and power down

Usage:   shutdown [-akrhPHfFnc] [-t sec] time [warning message] -a:     use /etc/shutdown.allow -k:     don't really shutdown, only warn. -r:     reboot after shutdown. -h:     halt after shutdown. -P:     halt action is to turn off power. -H:     halt action is to just halt. -f:     do a 'fast' reboot (skip fsck). -F:     Force fsck on reboot. -n:     do not go through "init" but go down real fast. -c:     cancel a running shutdown. -t secs: delay between warning and kill signal. ** the "time" argument is mandatory! (try "now") **
 * Or use /sbin/shutdown

reboot

 * execute
 * /sbin/reboot