People are always amazed when I tell them they can achieve this basic functionality by using cron. Many of our websites use Sphinx, the excellent full text indexer, to allow site searches. Should the server ever reboot, we need to make multiple search daemons start back up. Take the following line from a crontab:

crontab -l
 
@reboot /usr/local/bin/searchd --config ~/conf/sphinx.conf

This will make sure the searchd daemon starts on bootup.

Also there are a few other shortcuts you can use:

@yearly        Run once a year, "0 0 1 1 *".
@annually      (same as @yearly)
@monthly       Run once a month, "0 0 1 * *".
@weekly        Run once a week, "0 0 * * 0".
@daily         Run once a day, "0 0 * * *".
@midnight      (same as @daily)
@hourly        Run once an hour, "0 * * * *".

See man 5 cron for more information.

(And to be pedantic, @reboot is run when cron is started or restarted, not necessarily the OS itself. So /etc/init.d/cron restart would trigger that line to be run. You may want to keep that in mind.)