SleepWatcher monitors the Mac's sleep, wakeup, and idleness. It can be used to execute Unix commands when the Mac is in sleep mode, wakes up, or after a certain time without user interaction. It can also send the Mac into sleep mode or retrieve the time since the last user activity. The download includes a StartupItem, sample sleep scripts and source code for sleepwatcher. This software requires some knowledge of Unix commands to be useful.