#!/bin/sh

# I (Michael De Roover) do not own this code. Many thanks to Stack Exchange user Andy (http://unix.stackexchange.com/users/187608/andy) for submitting it on http://unix.stackexchange.com/a/307097.

PATH=/usr/bin

XUSERS=($(who|egrep "\(:[0-9](\.[0-9])*\)"|awk '{print $1$5}'|sort -u))
for XUSER in $XUSERS; do
    NAME=(${XUSER/(/ })
    DISPLAY=${NAME[1]/)/}
    DBUS_ADDRESS=unix:path=/run/user/$(id -u ${NAME[0]})/bus
    sudo -u ${NAME[0]} DISPLAY=${DISPLAY} \
                       DBUS_SESSION_BUS_ADDRESS=${DBUS_ADDRESS} \
                       PATH=${PATH} \
                       notify-send "$@"
done