See L<NOTIFICATION DATA FORMAT> below for a description of the data passed to
these programs.
-=begin comment
-
-=item C<NagiosExec>
-
-The executable is treated as a Nagios plugin. That means that the first line
-printed to C<STDOUT> by this program is used as the text of a notification and
-the severity of the notification depends on the exit status of the executable
-only.
-
-For information on how to write Nagios plugins please refer to the Nagios
-documentation. If a plugin works with Nagios but not with collectd please
-complain on the collectd mailing list instead.
-
-=end comment
-
=back
=head1 EXEC DATA FORMAT
data-sets is available in the B<types.db> file. See L<types.db(5)> for a
description of the format of this file.
-The I<OptionList> is an optional list of I<Options>, where each option if a
+The I<OptionList> is an optional list of I<Options>, where each option is a
key-value-pair. A list of currently understood options can be found below, all
-other options will be ignored.
+other options will be ignored. Values that contain spaces must be quoted with
+double quotes.
I<Valuelist> is a colon-separated list of the time and the values, each either
-an integer if the data-source is a counter, of a double if the data-source if
+an integer if the data-source is a counter, or a double if the data-source is
of type "gauge". You can submit an undefined gauge-value by using B<U>. When
submitting B<U> to a counter the behavior is undefined. The time is given as
epoch (i.E<nbsp>e. standard UNIX time).
=item B<message=>I<Message> (B<REQUIRED>)
Sets the message of the notification. This is the message that will be made
-accessible to the user, so it should contain some useful information. This
-option must be the last option because the rest of the line will be its value,
-even if there are spaces and equal-signs following it! This option is
-mandatory.
+accessible to the user, so it should contain some useful information. As with
+all options: If the message includes spaces, it must be quoted with double
+quotes. This option is mandatory.
=item B<severity=failure>|B<warning>|B<okay> (B<REQUIRED>)
or B<type_instance> without B<type> doesn't make much sense and should be
avoided.
-Please note that this is the same format as used in the B<unixsock plugin>, see
-L<collectd-unixsock(5)>.
+=back
=back
+Please note that this is the same format as used in the B<unixsock plugin>, see
+L<collectd-unixsock(5)>.
+
When collectd exits it sends a B<SIGTERM> to all still running
child-processes upon which they have to quit.
=back
+=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.
+
=head1 CAVEATS
=over 4