Scheduling StartUp and ShutDown

For a one-time shutdown you can use

shutdown -h 02:00

To schedule it you can use cron. There are some GUIs for it like gnome-schedule.

But to start machine on schedule you have to look at BIOS/UEFI settings.

Update: check the answers about MythTV and Wake on Plan below to schedule startup.

MythTV is able to shut down computer when it's no longer in use and wake it up a few minutes before the next recording starts. It does it by using ACPI functions to set wakeup time before shutting down. There is an extensive howto on configuring this, which basically boils down to:

First verify that your Linux kernel is 2.6.22 or newer and the HWclock update function has been disabled as described above.

Simple test to wake the machine 5 minutes from now

sudo sh -c "echo 0 > /sys/class/rtc/rtc0/wakealarm"
sudo sh -c "echo `date '+%s' -d '+ 5 minutes'` > /sys/class/rtc/rtc0/wakealarm"
cat /sys/class/rtc/rtc0/wakealarm

Check

cat /proc/driver/rtc

This should return a list of parameters. Check the "alrm_time" is 5 minutes into the future and the "alrm_date" is today.

Shutdown your computer and see if it comes back up in ~5 min.

sudo shutdown -h now  

(in Ubuntu 10.4 "sudo shutdown -P now" (-h may cause system to restart))

Of course, if you always need to shut the computer down at the same time and wake it up at the same time, you can just configure wake-up time in bios (if there's such an option) and schedule a shutdown right from init scripts

Use a cronjob to auto sleep and auto resume. The command below will put the the computer to sleep at 02.00 AM and start the machine 4 hours later (14400 seconds)

00 2 * * * root /usr/sbin/rtcwake -m off -s 14400