Get desktop notifications about apcupsd events on Linux (like you would on Windows with the tray app)

apcupsd-notify.service

# ~/.config/systemd/user/apcupsd-notify.service

# $ systemctl --user daemon-reload
# $ systemctl --user enable --now apcupsd-notify

[Unit]
Description=apcupsd notify
ConditionPathExists=/var/log/apcupsd.events

[Service]
Type=simple
ExecStart=%h/bin/apcupsd-notify.sh
Restart=always

[Install]
WantedBy=graphical-session.target

apcupsd-notify.sh

#!/bin/bash

f="/var/log/apcupsd.events"
curr=$(<"$f")

inotifywait -m -e modify "$f" --format "%e" | while read -r event; do
	if [ "$event" == "MODIFY" ]; then
		prev="$curr"
		curr=$(<"$f")
		[ "$curr" == "$prev" ] || notify-send -u critical -a apcupsd "${curr##*$'\n'}" && echo "${curr##*$'\n'}"
	fi
done