SleepWatcher is a command line tool (daemon) for macOS that monitors sleep, wakeup and idleness of a Mac. It can be used to execute a Unix command when the Mac or the display of the Mac goes to sleep mode or wakes up or after a given time without user interaction. It also can send the Mac to sleep mode or retrieve the time since last user activity. A StartupItem, sample start and sleep scripts and the source code for sleepwatcher are included in the download. A little bit knowledge of the Unix command line is required to benefit from this software.