You should always use one of the following (where you need to be root):
$ su -c '/sbin/halt' # To shutdown immediately
$ su -c '/sbin/reboot' # To reboot the machine immediately
$ su -c '/sbin/shutdown <other arguments>'
# To shutdown or reboot sometime in the futureYou must be careful to shutdown the machine properly, because data in memory may not have been written to disk yet (among other reasons). -- Eric G. Miller Powered by the <A HREF="http://www.debian.org">POTATO</A>!

