Cron
The Linux way to schedule commands.
http://www.adminschoice.com/crontab-quick-reference
Setting up a script to run a script in your home folder every five minutes (and log it)
crontab -e
and edit it to something like
*/5 * * * * /home/mmurtaugh/xpub.sh > /home/mmurtaugh/xpub.log