+=head1 ENVIRONMENT
+
+The following environment variables are set by the plugin before calling
+I<exec>:
+
+=over 4
+
+=item COLLECTD_INTERVAL
+
+Value of the global interval setting.
+
+=item COLLECTD_HOSTNAME
+
+Hostname used by I<collectd> to dispatch local values.
+
+=back
+
+=head1 USING NAGIOS PLUGINS
+
+Though the interface is far from perfect, there are tons of plugins for Nagios.
+You can use these plugins with collectd by using a simple transition layer,
+C<exec-nagios.px>, which is shipped with the collectd distribution in the
+C<contrib/> directory. It is a simple Perl script that comes with embedded
+documentation. To see it, run the following command:
+
+ perldoc exec-nagios.px
+
+This script expects a configuration file, C<exec-nagios.conf>. You can find an
+example in the C<contrib/> directory, too.
+
+Even a simple mechanism to submit "performance data" to collectd is
+implemented. If you need a more sophisticated setup, please rewrite the plugin
+to make use of collectd's more powerful interface.
+