self:
with self; ''
status=$(cat /sys/class/power_supply/BAT0/status)
if [ $status != "Discharging" ]; then
  exit 0
fi

capacity=$(cat /sys/class/power_supply/BAT0/capacity)
if [ $capacity -lt 20 ]; then
  export DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/$(id -u)/bus
  ${libnotify}/bin/notify-send -u critical "Battery ''${capacity}%"
fi
''