lock_key.zsh

#!/usr/bin/env zsh

# choose a sound theme folder of your choice
_sound="/usr/share/sounds/Pop/stereo/notification"

_print(){
    echo "{\"caps_lock\":\"$CAPS\",\"num_lock\":\"$NUM\"}"
}

_detect(){
    if [[ $_count != 0 ]]; then
        if [[ $NUM == "off" ]]; then
            dunstify -r 696 -t 5000 -u critical "Report" "Numlock was turned OFF"
        else
            dunstify -C 696
        fi

        if [[ $CAPS == "on" || $NUM == "off" ]]; then
            paplay $_sound/device-added.oga &
        else
            paplay $_sound/device-removed.oga &
        fi
    fi
}

_stale(){
    if [[ $num_old != $num_new || $caps_old != $caps_new ]]; then
        num_new=$num_old
        caps_new=$caps_old

        _print; _detect
    fi
}

# initial run check variable
_count=0

# begin monitoring
xkb -s1 | while read _ CAPS NUM; do
    num_old=$NUM
    caps_old=$CAPS

    _stale

    _count=1
done