Linux shutdown essentials

Mainly around

Sync

Shutdown

Reboot these instructions.

Write data synchronously to the LED order on the hard disk: Sync: Save to the hard drive before shutting down. In fact, sync can also be used in general account! Only the average account user's updated hard drive data only has its own data, not like root can update the entire system of data.
Customary shutdown instruction: shutdown
Reboot, Shutdown: Reboot, halt, Poweroff Halt will call shutdown first, and shutdown will eventually call halt

Linux shutdown essentials