View the running level of the CentOS server

Restart the test server using the command: shutdownnow (forgot to add-h) causes automatic restart and enters single-user mode. view the current system mode command: runlevelCentos system: [root @ fisheye ~] # Runlevel

Restart the test server using the command: shutdown now (forgot to add-h) causes automatic restart and enters single-user mode. view the current system mode command: runlevel

Centos system:

[Root @ fisheye ~] # Runlevel N 3

The RedHat series has seven runlevels)

Running Level 0: The system is down. The default running level cannot be set to 0. Otherwise, the system cannot start normally.

Running Level 1: Single-user working status, root permission, used for system maintenance, remote login prohibited

Running Level 2: Multi-user status (no NFS)

Running Level 3: full multi-user status (with NFS). log on to the console and go to the command line mode.

Operation Level 4: The system is not used and retained

Running Level 5: X11 console. log on to the GUI

Running level 6: The system is shut down and restarted normally. the default running level cannot be set to 6. Otherwise, the system cannot start normally.

The default runlevel of Ubuntu is 2.

 

Yong @ test2 :~ $ Runlevel N 2

Debian (ubuntu is based on debian) Linux has always been started with runlevel 2 by default, and the runlevel definition is different from redhat. The runlevel of debian is defined as follows:

0-Halt, shutdown mode

1-Single, Single-user mode

2-Full multi-user with display manager (GUI)

3-Full multi-user with display manager (GUI)

4-Full multi-user with display manager (GUI)

5-Full multi-user with display manager (GUI)

6-Reboot, restart

2 ~ There is no difference in level 5. They are in multi-user mode, which is different from general linux.