acpid 1.0.6-9ubuntu4.9.04.3 (i386 binary) in ubuntu jaunty

 Modern computers support the Advanced Configuration and Power Interface (ACPI)
 to allow intelligent power management on your system and to query battery and
 configuration status.
 .
 ACPID is a completely flexible, totally extensible daemon for delivering
 ACPI events. It listens on a file (/proc/acpi/event) and when an event
 occurs, executes programs to handle the event. The programs it executes
 are configured through a set of configuration files, which can be
 dropped into place by packages or by the admin.