I never realised the shutdown command extended further, where you can specify a time to shutdown or shutdown the system in (x) amount of minutes.
To shutdown your system at a specific time, it must be entered the following format HH:MM
So to shutdown your system at Two Twenty PM in the afternoon we enter the following command
sudo shutdown 14:20
To shutdown your system after (x) amount of minutes, it must be entered in the following format +m
So to shutdown the system after 20 Minutes enter the following command
sudo shutdown +20
You can also add a message when the shutdown command is initiated, for example shutting down
sudo shutdown +20 "Shutting Down....."
To reboot your system at Ten PM in the evening we enter the following command
sudo shutdown -r 22:00 "Rebooting..."
You could create a cron job to reboot your system once a month, once a week, once a day and so on. Cron jobs are discussed in my other tutorial, which can be found here
To cancel a scheduled shutdown or reboot of your system, you can use the following command