This is a simple tip, how to execute some file in computer startup. (I used this tip to enable the port forward on startup)
Copy your file to /etc/init.d/ using "cp file /etc/init.d/file"
Edit /etc/rc.local (as root) and add the file that you want to execute. You must use the full path like /etc/init.d/file.sh for example.
The file must have execution permissions, do this using "chmod +x /etc/init.d/file.sh"
PS: You must add the line before "exit 0" in rc.local