How to add bash scripts on startup.

update-rc.d

<pre lang="bash">
sudo cp /path/to/yourscript.sh /etc/init.d/yourscript.sh
sudo update-rc.d /etc/init.d/yourscript.sh defaults
chmod +x /etc/init.d/yourscript.sh

Root Crontab

<pre lang="bash">
sudo crontab -e
@reboot /path/to/yourscript.sh