APCUPSD can be used for power management and controlling most of APC's
UPS models on Unix and Windows machines. Apcupsd works with most of
APC's Smart-UPS models as well as most simple signalling models such
as Back-UPS and BackUPS-Office.

This buildscript veers from the "accepted" installation of apcupsd,
but for what I believe you'll see are justifiable reasons. The stock
install of apcupsd detects its presence on Slackware and attempts to
patch the system's /etc/rc.d/rc.6 script and places the rc.apcupsd
script inside /etc/rc.d (instead of DESTDIR/etc/rc.d - in essence, it
touches files outside DESTDIR). I don't view this as even remotely
acceptable, so the build script disables the distribution-specific
installation to prevent messing with files outside DESTDIR;
however, this does make it require some manual configuration after
installation.

After installing, see /usr/doc/apcupsd-3.14.13/README.SLACKWARE for more
information on how to modify rc.6 and how to start the apcupsd daemon 
automatically at boot.