The ruptime command gives a status line like uptime
for each machine on the local network; these are formed from packets
broadcast by each host on the network once a minute.
Machines for which no status report has been received for 5 minutes are
shown as being down.
ruptime takes the following options:
Count even those users who have been idle for an hour or more.
Sort the display by load average.
Reverse the sorting order.
Sort the display by up time.
Sort the display by number of users.
Normally, the listing is sorted by host name, but this order can be
changed by specifying one of the options listed below.
Note that, for ruptime to work properly,
the directory /var/spool/rwho
must be created by the system administrator.
Given the adverse effect rwho can have
on system and network performance,
the system administrator must decide whether
the benefits of the rwho feature are worth the performance cost.