We have a laptop cart with a bunch of Dell Latitude 5490's running Ubuntu Desktop 18.04. I'd like these to reboot nightly at 4 am. The cron job is simple enough, but it never runs because the laptops are hibernating with their lids closed.
I looked at rtcwake but documentation is confusing -- are RTC, BIOS clock, and hardware clock all different things? Sometimes these terms seem to be used interchangeably and sometimes not. My laptops sync their clocks to our NTP server (UTC - 4) but the BIOS clock still show UTC + 0.
Setting a startup time in the BIOS didn't work either, and I tried it both with local time and UTC.