how to see active users

I have a dual boot W7/Ubuntu laptop.

First question: My understanding is that some software creates a username for itself and that user somehow becomes an active user when the console user executes the software. So if user "y" at the console executes "program a", then program a may be able to execute as user "program a". Is this correct? If not, what am I misunderstanding?

Second question: How can I see what users are currently active on my machine? Ubuntu shows the active console user in the upper left corner, but is it possible there are other users?

I would like to know the answers to the same question for W7, maybe I'll ask it in another forum.

 

In terminal:-
last -nX where X is a number (eg. last -n6)

 

Hi lurningcerv,

In Ubuntu/Linux use the id command to print real and effective user and group IDs of active users. Read the man page for the command id: man id

-- Tom

 

The goal in this is often running apps with limited privileges, directory access, etc. For example, OpenVPN needs to start as root, in order to change network configuration, but then drops to user nobody, with very limited privileges.