Who is logged in on local machines
The rwho utility produces output similar to who, but for all machines on the local network. If no report has been received from a machine for five minutes, rwho assumes the machine is down, and doesn't report users last known to be logged into that machine.
If a user hasn't typed to the system for a minute or more, rwho reports this idle time. A user who hasn't typed to the system for an hour or more is omitted from the output of rwho unless the -a option is given.
The rwho utility requires the libsocket.so shared library.
This utility is unwieldy when the number of machines on the local net is large. It's unreliable due to protocol issues.