This is how to set a program (or daemon) to run at boot. For example, if you want to run at cron at boot (which you would) issue the following as root.
/sbin/chkconfig –add crond
/sbin/chkconfig –level 2345 crond on
You can then confirm that it has worked by looking at /etc/rc.d/rc2.d/S<number>crond (eg S90crond).
