Making script run at boot time in debian

Debian uses the sys-V like init system for executing commands when system run level changes such as bootup and shutdown time.

If you want to add a new script to start at a machine boot.
You should copy a script to the directory /etc/init.d/.
make sure that is executable by running #chmod 755 /etc/init.d/example.sh
The simplest way to doing this is to use the command update-rc.d

#update-rc.d example.sh defaults

If you want to remove the script from the startup sequence in future run the command like this:
#update-rc.d -f example.sh remove

You can find the more information of that command on manuals.Run #man update-rc.d