2. System V Service
There are many command line tools you can use to manage Sys V services.
List services
$ service --status-all
Start a service
$ sudo service networking start
Stop a service
$ sudo service networking stop
Restart a service
$ sudo service networking restart
These commands aren't specific to Sys V init systems, you can use these commands to manage Upstart services as well. Since Linux is trying to move away from the more traditional Sys V init scripts, there are still things in place to help that transition.
Exercises
Manage a couple of services and change their states, what do you observe?