There are several options available with shutdown command that can be used to power off Linux system. One example is -h option, which means to halt the system after it has been brought down. We can add other things such as a comment message when invoking shutdown -h command. As you can see from the example of Ubuntu restart post before, we have to specify a time argument after the shutdown option so the system know when to shutdown the system. Here are some examples on how to power off Ubuntu server using shutdown command with other things that you can do:
1) Using Linux shutdown command with -h option example:
luzar@ubuntu:~$ sudo shutdown -h now
[sudo] password for luzar:
Broadcast message from luzar@ubuntu
(/dev/pts/0) at 11:32 ...
The system is going down for halt NOW!
The example above show a basic shutdown command used to power off Ubuntu server. We used '-h' option and a time argument 'now' which means to bring down the system after we press enter.
2) Using Linux shutdown command -p option example:
luzar@ubuntu:~$ sudo shutdown -h -P +1
Broadcast message from luzar@ubuntu
(/dev/pts/0) at 11:47 ...
The system is going down for power off IN ONE MINUTE!
The example above shows the '-P' option is added after the '-h' option. The -P option means 'power off'. When -P is used after -h option, it means we tell the system to power off after the system halt. Also this time we used +1 in the time argument. That means we want to bring down the system after 1 minute.
3) If you have to warn all your users, you can write a message after the time argument. See the example below:
luzar@ubuntu:~$ sudo shutdown -h -P +3 Please save your work now!
Broadcast message from luzar@ubuntu
(/dev/pts/0) at 11:57 ...
The system is going down for power off in 3 minutes!
Please save your work now!
shutdown: Shutdown cancelled
If you want to cancel shutdown after invoked the command, you can press Ctrl+C combination keys. That will work if you do not use the 'now' time argument. If you just want to warn users to log out and prevent other user to login without actually bring the system down, you can use '-k' option.
luzar@ubuntu:~$ sudo shutdown -k +3 Please save your work now!
Broadcast message from luzar@ubuntu
(/dev/pts/0) at 12:11 ...
The system is going down for maintenance in 3 minutes!
Please save your work now!
luzar@ubuntu:~$
That's all.
