shutdown-at-night binary package in Ubuntu Mantic amd64

 With this tool you can schedule regular shutdowns of workstations in the
 evening, and also wake them up every morning, using either nvram-wakeup, ACPI
 wakeup or wake-on-lan.
 .
 For the wake-on-lan wake-up sequence you need one awake machine on your local
 network / subnet. This can be a server machine or a client machine that got
 just previously woken up by nvram-wakeup.
 .
 The shutdown sequence will be initiated hourly after 4pm via a CRON job.
 However, only machines that appear inactive / unused will be shut down.
 Machines that are currently in use will remain up and running.
 .
 The Shutdown-at-Night tool can be activated via a config file or via
 membership in a NIS netgroup called shutdown-at-night-hosts.

Source package