Seven operating levels and level changes for Linux

Run Level level description

0 All processes will be terminated, the machine will stop orderly, the system is at this runlevel when shutting down

1 single-user mode for system maintenance with only a few processes running and all services not booting

2 Multi-user mode, same as Run Level 3, only the network Questionnaire system (NFS) service does not start

3 multi-user mode, allows multiple users to log on to the system, is the system's default boot level

4 custom run levels left to users

5 Multi-user mode, and run X-windows after the system starts, give a graphical login window

6 All processes will be terminated, system restarted

View Run Level

#runlevel

Temporarily switch the run level (automatically resumes after rebooting the system)

#init level number

Enter the graphical interface (init 5, if the system has a graphical interface installed)

#startx

To modify the system default run level

#vim/etc/inittab

Initdefault

Seven operating levels and level changes for Linux