A simple command can be entered in the Terminal to schedule a time for the system to shut down.
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Go to Applications (or Main Menu) > Accessories > Terminal.
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Enter sudo shutdown -h +m (replace m with the number of minutes, e.g. +60).
OR: enter sudo shutdown -h hh:mm (replace hh:mm with the time on the 24hr clock, e.g. 23:15).
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Enter password and minimize the Terminal window.
The system will then shut down within the minutes or at the time specified. To cancel a scheduled time, enter
sudo shutdown -c in the Terminal.
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Alternatively, you might want to download and install
GShutdown, which is a GUI program for scheduling a time to shutdown the system.
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