To determine who is using the network, enter the command finger. finger displays a list of all the users on the system, their hosts, and the date and time that they logged in. Users are listed by their logon id's, not their real names. To identify an individual (and show some other useful information about that user) enter:
finger -l <loginId>
Finger can also be used to locate another users account name. For example, the command
finger -l foo
Will show something users who have `Foo' in their real names like:
Foobius Barus (foobar) Home: /sulu/foobar Last login on ttyp7 from boromir, on Fri Sep 6 11:41:49 1991 No mail. No plan.