Run Level Numbers

Run levels

A run level is a state of init and the whole system that defines what system services are operating. Run levels are identified by numbers.

Run level numbers

0 Halt the system.

1 Single-user mode (for special administration).

2 Local Multiuser with Networking but without network service (like NFS)

3 Full Multiuser with Networking

4 Not Used

5 Full Multiuser with Networking and X Windows(GUI)

6 Reboot.