Adding a startup script that always runs at boot time

You have a script that you need to run everytime your system boots? say, for example you need to dial up to connect to internet. Its very simple and straight forward:-

Write a script and add it to your /etc/init.d/ directory, say your script's name is wvdial.sh

$ mv wvdial.sh /etc/init.d/

$ update-rc.d wvdial.sh defaults

that's all... now boot your system and tada... no more typing in commands on the terminal after boot to do those daily bootup tasks!