The query handler also includes the NERD (Nagios Event Radio Dispatcher) service, which allows you to subscribe to the service or host check results. The service name is @nerd and it accepts the following commands:
@nerd list\0 @nerd subscribe <channel>\0 @nerd unsubscribe <channel>\0
The list command returns a list of channels separated by newlines, where the channel name is the first word of a line, followed by the channel's description. The subscribe and unsubscribe commands can be used to start and stop the receipt of notifications for specified channels.
For example, to list all available channels, we can simply use the following command from the shell:
# echo -e '@nerd list\0' | \ socat - UNIX-CONNECT:/var/nagios/rw/nagios.qh
The output will be as follows:
hostchecks Host check results servicechecks Service check results opathchecks Host and service checks in gource's log format