spy [v]
Spy prints a summary of who is on the system and what they are doing. The optional argument v (short for verbose) causes more detailed information to be given. The operation of this task is machine dependent, as is the quantity and format of the information returned.
cl> spy 4:36pm up 24 days, 5:42, 2 users, load average: 0.29, 0.15, 0.18 User tty login@ idle JCPU PCPU what roger ttyh8 4:21pm 15 8 5 -csh alice ttyh9 4:26pm 44 27 w