rwho man page
rwho — who is logged in on local machines
The rwho command produces output similar to who, but for all machines on the local network. If no report has been received from a machine for 11 minutes then rwho assumes the machine is down, and does not report users last known to be logged into that machine.
If a users hasn't typed to the system for a minute or more, then rwho reports this idle time. If a user hasn't typed to the system for an hour or more, then the user will be omitted from the output of rwho unless the -a flag is given.
information about other machines
finger(1), rup(1), ruptime(1), rusers(1), who(1), rwhod(8)
The rwho command appeared in 4.3BSD.
This is unwieldy when the number of machines on the local net is large.
ruptime(1), rusers(1), rwhod(8).