How to shut down the computer in linux?

There are several commands to choose from when shutting down in Linux. Let’s take a look at some commands from older versions first.

1. shutdown

The shutdown command safely shuts down the system. Shutdown performs its job by sending a signal to the init program, asking it to change the runlevel. Runlevel 0 is used to shut down (halt), and runlevel 6 is used to reactivate (reboot) the system.

For example:

Shutdown command: shutdown -h now

Restart command: shutdown -r now

2, halt

halt Shut down immediately is equivalent to shutdown -h now. In fact, halt is to call shutdown -h. When halt is executed, the application process is killed, the sync system call is executed, and the kernel is stopped after the file system write operation is completed. But this only stops the operating system and the power supply is still working.

3. Poweroff

Poweroff will first shut down the system, and then send a power-off signal to acpi.

4. init

init is the ancestor of all processes. Its process number is always 1, so sending the TERM signal to init will terminate all user processes and daemons. Process etc.

init is the command to switch the execution level. Linux has a total of 7 execution levels, the more important ones are the following 4 levels:

• run level 0: shutdown

• run level 3: pure Command line mode

• run level 5: Contains graphical interface mode

• run level 6: Restart

5. Reboot

The working process of reboot is almost the same as halt. However, it causes the host to restart, while halt causes a shutdown.

Now

Now the new release version uses systemd. These commands are softly connected to systemctl or systemd, which means that shutdown and power management are now It's systemd that takes over, so the commands are the same.

systemctl [Command]

• halt Enter the system halt mode. The screen may retain some messages, which is related to your power management mode.

• poweroff enters the system shutdown mode. Shut down directly without providing power!

• reboot Restart directly

• suspend Enter sleep mode

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