This post looks at how to run additional scripts or applications at system startup / system boot up on Linux. I can confirm that this works on CentOS (and should therefore work on Red Hat Enterprise Linux from which is it derived, and Fedora and Fedora based distros) and Debian (and therefore on Debian derived distros).
After all the other processes are started by the init command at boot time, the following script is run on Red Hat / CentOS based systems:
/etc/rc.d/rc.local
And this script on Debian based systems:
/etc/rc.local
You can put your additional commands or scripts to run into this script with the knowledge that everything else has already started up, and doesn’t require the complex initialisation scripts that appear in the /etc/rc.d/init.d or /etc/init.d directory.