How to disable a service from startup in Ubuntu?
Answer:
For example, to turn off apache2 from startup, use
sudo update-rc.d -f apache2 remove
When the system restart, apache2 will not be running anymore.
But, if you want to add them back later, you can use
sudo update-rc.d -f apache2 defaults
[...] In newer version of Ubuntu such as 10.04, some services are managed by upstart and you cannot disable them by using the old method. [...]