- 1 : single-user
- 2 : multi-user, no network
- 3 : multi-user, with network
- 4 : not defined
- 5 : multi-user, network with graphics
- 6 : no runlevel, used to reboot
This means for example that runlevel 3 includes the service network.
You can find out your current runlevel with the command
You can change your runlevel with the command
where runlevel is a number from 1 to 6.
When you boot a Linux system, you can hand over the runlevel you want to boot into as a kernel parameter. See boot process. If you do not use a kernel parameter, the system will look for the configuration in /etc/inittab.
The services itself are system V initscripts.