Is there a way to see if (and which) a user has logged on to an (Ubuntu) Linux machine via NoMachine - similar to when a Windows machine shows which user is remotely using it?
when logging in from a nx client, in fact you get a remote display so you see something like this when using 'w';
As you see, root is logged in from tty pts/5 (from a remote location through a text ssh client) en the rest from :number. When you see these ttys, then you know those are graphical sessions.
You can also use 'who' (which has an easier format to parse if you need to do that):