Run Levels in openSUSE & SUSE Linux

Run level 1

Single User Mode – Very limited access to system resource including the file systems where only the root file system is mounted and most if not all services are shutdown. Idealy used for system maintenance.

To switch to this mode,

yoga:~ # shutdown

or 

yoga:~ # init 1

or 

yoga:~ # init S

The shutdown command takes the openSUSE Linux down and leaves it in the single user mode.

Run level 2

Text mode – Local Multi-User mode without network support

To switch to this mode,

yoga:~ # init 2

Run Level 3

Text mode with Networking – Text mode multiuser mode same as Run level 2 with network support.

To switch to this mode,

yoga:~ # init 3

Run Leve 4
Not used

Run Level 5 (default)

Multi User GUI – This is the default GUI mode with Multi-user network support.

To switch to this mode,

yoga:~ # init 5

Run level 6

System Reboot – Reboots and logons onto the default system run leve (Run level 5 in openSUSE)

To switch to this mode,

yoga:~ # init 6 

or 

yoga:~ # reboot 

or 

yoga:~ # shutdown -r

if want run level running when system reboot, edit /etc/inittab