How to Switching or Changing Between Different Runlevels on Linux

linuxThe runlevel is a software configuration of the system which allows only a selected group of processes to exist. 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 )

How to Check and Display Runlevel on Unix or Linux System

In this post, i will show two method to switching or changing between different runlevels on linux. The steps has been tested on CentOS 6.2.

READ  How to Find the Release Version of Your Linux/Unix

Method 1. Changing run level temporarily without reboot :

In order to change the run level immediately without reboot, you can use init command. Assumed that you are currently in the default run level 3 and want to switch to run level 1 which is will enter single user mode, execute “init 1” :

[root@centos62 ~]# init 1

To shutdown the system, execute “init 0” :

[root@centos62 ~]# init 0

To reboots the system, execute “init 6” :

[root@centos62 ~]# init 6

Please note that above command is not permanent and the system will return to default run level after reboot.

READ  How to Automatically Forward Gmail Emails to Other Email Address

Method 2. Changing the run level permanently :

[root@centos62 ~]# vi /etc/inittab

Let assumed the default run level is 3.


Change the initdefault to 5 as below :


Leave a Reply

Your email address will not be published. Required fields are marked *