Assuming you're not root (it doesn't matter though), this is just an example from my terminal(&shell) to show what users are connected..
6:57AM up 4 days, 13:44, 1 user, load averages: 0.06, 0.08, 0.08
USER TTY FROM LOGIN@ IDLE WHAT
crunch p0 cypher 6:57AM 0 w
So you can either type, 'w', or 'who'. I'm sure it won't make the greatest of differences.