How to identify users that have su'ed to a different account?

Hello and thanks in advance for anyone that can offer me any help with this!

I'm trying to figure out a quick & easy way to see a list of everyone's effective user id... I would have thought 'w' or 'who' would be able to display if someone had switched user accounts... but it's only showing the real user ID they logged in with.

Once against... thanks for any help!

How about ps with the "euid" output "standard format specifier"? man ps :

Maybe that

getent passwd nez
>nez:x:1000:1000:nezabudka:/home/nez:/bin/bash
getent group wheel qemu
>wheel:x:10:nez
>qemu:x:107:nez
getent initgroups nez
>nez                   10 107 983 1000

In Linux you can do

pstree -pu

A process name is followed by (pid,newuser) if the user was changed to newuser.