[Libguestfs] [PATCH nbdkit] docs: Suggest how to detect if a filter is installed.

[Richard W.M. Jones]

Thanks: Eric Blake, Martin Kletzander.
---
 docs/nbdkit-probing.pod | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/docs/nbdkit-probing.pod b/docs/nbdkit-probing.pod
index 94bdfb4..46a7c47 100644
--- a/docs/nbdkit-probing.pod
+++ b/docs/nbdkit-probing.pod
@@ -80,6 +80,17 @@ installed.  A complete shell script which does this is:
      fi
  done
 
+=head2 Detect if a filter is installed
+
+To find out if a filter is installed (and working) use
+I<--dump-plugin> with the C<null> plugin and the name of the filter to
+test:
+
+ nbdkit --dump-plugin --filter=foo null
+
+This will fail with an error and non-zero exit code if the C<foo>
+filter cannot be loaded.
+
 =head1 SEE ALSO
 
 L<nbdkit(1)>.
-- 
2.23.0