Linux advanced system startup process diagram

1:linux start is a very complicated process, in order to better understand, drew a time series start diagram.

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2: Run Level

The Linux system has 7 runlevel (runlevel):

• RunLevel 0: System down state, system default RunLevel cannot be set to 0, otherwise it will not start normally

• RunLevel 1: Single User working status, root privilege, for system maintenance, remote login Forbidden

• RunLevel 2: Multi-User State (no NFS)

• RunLevel 3: Full multiuser State (with NFS), enter console command line mode after login

• Run Level 4: System not used, reserved

• Run level 5:x11 console, login to GUI mode

• RunLevel 6: The system shuts down gracefully and restarts, the default runlevel cannot be set to 6, otherwise it will not start normally

3:linux shut down the machine

Sync synchronizes the data from memory to the hard disk. Shutdown shutdown instructions, you can look at the help documentation for man shutdown. For example, you can run the following command to shut down: shutdown–h ' This server would shutdown after the mins ' This command tells you that the computer will shut down after 10 minutes and will be displayed in the login user's current screen. Shutdown–h now immediately shuts down Shutdown–h 20:25 the system shuts down at 20:25 today, Shutdown–h +10 10 minutes after shutting down the machine shutdown–r the system immediately restarts Shutdown–r +10 system restarts after 10 minutes Reb Oot is the restart, equivalent to the Shutdown–r nowhalt shutdown system, equivalent to Shutdown–h now and Poweroff

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Linux advanced system startup process diagram