Ubuntu uses upstart instead of sysvinit. However there are still runlevels and the links in them.

I have installed tor and it has added itself to the startup of the OS. Now I want to remove it and the popular options are to remove the links of starting and stopping the service from runlevels or make the /etc/init.d/ script non-executable. This is fine but this will be problematic in case I want to put tor again on the startup list. How would I know to put the proper sequences in the proper runlevel directories.

Is there any complete guide given? What are the rules for this? Any tools to manage the init?

Please tell