Identify user in a Bash script called by sudo

Question

If I create the script /root/bin/whoami.sh containing:

#!/bin/bash
whoami

and this script is called by a user with a properly

Answer 1

Using whoami, who am i, who, id or $SUDO_USER isn't right here.

Actually, who is never a solution to the question, as it will only list the logged in users, which might be dozens...

In my eyes, the only valuable answer is the use of logname.

Hope this helps

Rob