- Open a terminal session
- sudo -i and enter the root password
- who -r
- will display your current run level
- cat /etc/inittab
- will list the available run level
- Deb/Ubu
- telinit <runlevel>
- example: telinit 1
- will change you to single user for administrative tasks
- RHEL/CentOS
- systemctl list-units –type=target
- example: systemctl isolate runlevel1.target
- will change you to single user for administrative tasks
|
Run Level
|
Mode
|
Action
|
|---|---|---|
| 0 | Halt | Halts the system. Run Level 0 is a not to be used as the default run level, otherwise the system will never come up. Because the system would shutdown the second the kernel launches init process. |
| 1 | Single-User Mode/Maintenance Mode | Does not configure network interfaces, start daemons, or allow non-root logins |
| 2 | Multi-User Mode | Debian’s default runlevel. On RHEL, runlevel2 starts without NFS file sharing and without X Window System. (No GUI) |
| 3 | Multi-User Mode with Networking | RHEL’s default runlevel. Multi-user mode with networking but with no GUI |
| 4 | Undefined | Not used/User-definable |
| 5 | X11 | Multi-User mode with X11 started and GUI is running |
| 6 | Reboot | Reboots the system. Should not be used a the default run level because it will cause infinite reboots |
