Shutting down a Linux Box using at

I recently had a need to shutdown a firewall box of mine so that a power outage wouldn't catch it while it was still up.

The `at' command give you the ability to run a job once at a certain time. Cron on the other hand handle repetitive events.

Fedora Core 1 - at command

To use the at command the atd daemon must be running

On Redhat FC1 use ntsysv or chkconfig to check the atd service is activated
chkconfig atd on

chkconfig --list atd

atd            
0:off   1:off  
2:off   3:on   
4:on    5:on   
6:off

and then run

/etc/rc.d/init.d/atd start