I have found a couple Debian based distributions that have trouble turning off services at start up. To begin, services are background jobs that run on *nix systems. In compression to Windows they are what you can find by opening the task manager and finding the processes. You don't see the programs running because they are in the back ground. Most of these services are harmless but unnecessary. To stop a service in a Debian system type in the command.
sudo service servicename stop
sudo /etc/init.d/servicename stop
This stops the service running while the system is running. Replace the service with the name of the service. The best way to see what the service is called it by typing
If you can't find the service then try
ps aux | grep servicename
sudo kill -9 PID
to stop the service.
Now the trouble, when trying to stop the script to activate the service at start up it is
sudo update-rc.d -f servicename remove
This command will remove the smybolic links between the startup scripts in the /etc/init.d/servicename
It seems that a couple Debian distributions have changed the way startup scripts work. You wouldn't want an administrator or anyone that had root or sudo access to turn off a service by mistake or purpose. After searching I found a command that will write an orerride file that the /etc/init.d files will search for before running a service.
echo manual | sudo tee /etc/init/servicename.override
I have tried this command in Ubuntu and Zorin right now and rebooted both and the services I want to stay off have stayed off. If I need to turn them on, I will do it manually then turn them off. This helps ti keep an eye on which services are running and being able to control them.