Redhat: Grub runlevels

Run Levels

There are seven main run levels available. Each run level sets what services are available.

0	Halt
1	Single user
2	Multiuser, some networking, command line
3	Multi User, Netwoking, Command Line
4	Unused
5	X11 / GUI
6	Reboot

Switch Between Run Levels

The default run level is defined in /etc/inittab. It contains one line. Changing the number will change the run level the system boots into, in this case the GUI will be started if available. The default run level should never be set to 0 or 6.

id:5:initdefault:

To check the current run level run the 'runlevel' command

[root@head ~]# runlevel
N 3

The change the run level you can use the init or telinit commands.

[root@head ~]# init 3
5 3

If you were to set the run level to 0 the system would shut down, level 6 would cause the system to reboot.