This example shows the correct ways to check run level on unix or linux server. The runlevel is a software configuration of the system which allows only a selected group of processes to exist. The processes spawned by init command/process for each of these runlevels are defined in the /etc/inittab file. Usually runlevel 0, 1 and 6 are the same and reserved for the following purposes :
0 – halt
1 – single mode
6 – reboot
Meanwhile runlevel 2,3,4 and 5 used for the following :
2 – Multi-User Mode
3 – Multi-User Mode with Networking
4 – Not used/User-definable
5 – Start the system normally with appropriate display manager. ( with GUI )
1. Check and display runlevel using “who” command :
[root@centos62 ~]# who -r
run-level 3 2012-07-07 09:58
2. Check and display current and previous system runlevel using “runlevel” command :
[root@centos62 ~]# runlevel N 3