Through the SSH terminal, it is possible to shutdown your linux server by using the specific command. Eg:
sudo shutdown -h now
will immediately shut down the system. If you want to shut down the computer within a set time you will use:
sudo shutdown -h +30
(to turn off the computer in thirty minutes)
or
sudo shutdown -h 3103180830
(to turn off the computer on 31-03-2018 at 08:30)
Alternatively, it is also possible to use:
sudo halt
or
sudo poweroff