PowerSaveUPS is Macintosh only scriptable software for controlling UPS (Uninterruptible Power Supply) systems with USB (such as APC) Two shutdown thresholds are specified - Soft (Graceful) shutdown, and Hard (Ungraceful) shutdown which is instigated as a last resort. At Soft shutdown time, any scripts in the 'PowerSaveUPS Scripts' folder are executed. Typically these would be scripts that save any open documents as a time stamped 'PowerSave BU', followed by a 'graceful' shutdown script.