How to Use the Linux shutdown Command | Hostvento Knowledge Base

Basic use

Power off now:

sudo shutdown -h now

-h means halt (stop) and, on most systems, power off.

Schedule a shutdown

In 10 minutes:

sudo shutdown -h +10

At a specific time (24-hour clock):

sudo shutdown -h 23:30

Send a message

The message goes to all logged-in users:

sudo shutdown -h +10 "System will shut down in 10 minutes. Please save your work."

Cancel a shutdown

sudo shutdown -c

Restart

sudo shutdown -r now

Restart in 5 minutes:

sudo shutdown -r +5

Options

-h halt the system.
-P power off after halting.
-r reboot.
-c cancel a scheduled shutdown.
-k only send the warning, do not shut down.
--no-wall do not send the wall message.

The older options -i, -f and -t come from other systems and do not exist in the shutdown of current systemd-based Linux. To power off at once without a delay you can also run systemctl poweroff, and to restart systemctl reboot.

Use cases

Planned maintenance. Schedule a shutdown for a quiet hour.
Emergency. Stop the machine now to prevent damage.
Restart after updates, for example a kernel update.

Warning: On a remote server a shutdown turns the machine off, and you may not be able to turn it back on. Use -r (reboot) when you are connected through SSH, unless you have console or panel access.

Quick recap

shutdown -h now powers off, shutdown -r now restarts.
shutdown -c cancels a scheduled one.