A bash script to show connected users using your linux access point. This works with Network-Manger connection sharing also.
To run this in real time use the command:
watch bash showusers.sh
It will run the script every 2 seconds and you'll be able to see who connects and disconnects in near real time.
To share wifi in Ubuntu easily, follow the instructions here. [http://ubuntuhandbook.org/index.php/2014/09/3-ways-create-wifi-hotspot-ubuntu/]
Let me know if you find this useful.