Detailed explanation of shutdown command under Linux

The shutdown command can safely shut down or restart the Linux system. It prompts a warning message to all logged-in users on the system before shutting down the system. This command also allows the user to specify a time parameter, which can be a precise time or a period of time from now.
The format of precise time is hh:mm, which represents hours and minutes, and the time period is represented by + and minutes. The system will automatically perform data synchronization after executing this command.

General format of this command

Syntax: shutdown [-efFhknr][-t seconds][time][warning message]


Parameters:
-c When executing the "shutdown -h 11:50" command, Simply press the + key to interrupt the shutdown command.
　-f 　Do not execute fsck when restarting.
　-F Execute fsck when restarting.
-h Shut down the system.
　-k Just sends information to all users, but does not actually shut down the computer.
　-n does not call the init program for shutdown, but shutdown itself.
-r Restart after shutdown.
　-t How many seconds to delay between sending a warning message and deleting the message.
[Time] Set the time after which the shutdown command will be executed.
　[Warning message] Message to be sent to all logged in users.


It should be noted that this command can only be used by super users.

Example 1, the system shuts down immediately and restarts immediately after ten minutes

# shutdown –r +10
Example 2, the system shuts down immediately without restarting
# shutdown –h now