#!/bin/bash
# Send a notification message to all active graphical user sessions
# Usage: sudo ./notify_all_gui_users.sh "Your message here"

if [ -z "$1" ]; then
  echo "Usage: $0 \"message\""
  exit 1
fi

MESSAGE="$1"

loginctl list-sessions --no-legend | while read -r session uid user seat tty; do
  # Only graphical sessions
  if [[ "$seat" == seat* ]]; then
    BUS="/run/user/$uid/bus"

    if [[ -S "$BUS" ]]; then
        echo XNotify $user $uid $MESSAGE
        sudo -u "$user" \
        DBUS_SESSION_BUS_ADDRESS="unix:path=$BUS" \
        notify-send "$MESSAGE"
    fi
  fi
done