How to add a startup script on Debian linux

1) create your script (myscript) and add it to /etc/init.d/

2) make it executable: chmod 755 myscript

3) add the appropriate symbolic links: update-rc.d myscript defaults

If you want to remove the script from startup do the following:

$ update-rc.d -f myscript remove

Then remove the script from the init.d directory.

Reference