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System status daemon

Note: You must be root to start this daemon.


rwhod [-i interval] [-u user]

Runs on:



-i interval
Specify the broadcast interval in seconds, or in minutes if interval has a suffix of m. The default is 3 minutes; the maximum is 11 minutes because higher values will cause ruptime to mark the host as being down.
-u user
Drop privileges and become the specified user.


The rwhod daemon is the server that maintains the database used by the rwho and ruptime utilities. Its operation is based on the network's ability to transmit broadcast messages.

The rwhod daemon operates as both a producer and a consumer of status information. As a producer of information, it periodically queries the state of the system and constructs status messages that are broadcast on a network. As a consumer of information, it listens for other rwhod daemons' status messages, validating them, then recording them in a collection of files located in the directory /var/rwho.

The daemon transmits and receives messages at the port indicated by the rwho entry in the /etc/services file.

Messages received by the rwhod daemon are discarded unless they originated at an rwhod daemon's port. In addition, if the host's name, as specified in the message, contains any unprintable ASCII characters, the message is discarded. Valid messages received by rwhod are placed in files named whod.hostname in the directory /var/rwho. These files contain only the most recent message, in the format described above.

The rwhod daemon generates status messages about every three minutes.


The rwhod daemon requires the shared library.

See also:

ruptime, rwho