docs/administration-guide.rst: doc prune --dry-run

diff --git a/docs/administration-guide.rst b/docs/administration-guide.rst
index d5a60a55df162ac4c168a6e3c6bf1dcfdcbcf55a..a4406ce5bc6f5e01e41ce17bd24a9933bef18e8c 100644 (file)
--- a/docs/administration-guide.rst
+++ b/docs/administration-guide.rst
@@ -451,12 +451,25 @@ The prune command also looks for unfinished and incomplete backups and
 removes them unless they are newer than the last successful backup. In
 this case, the last failed backup is retained.
 
-
 .. code-block:: console
 
   # proxmox-backup-client prune <group> --keep-daily 7 --keep-weekly 4 --keep-monthly 3
 
 
+You can use the ``--dry-run`` option to test your settings. This just
+shows the list of existing snapshots and what action prune would take
+on that.
+
+.. code-block:: console
+
+  # proxmox-backup-client prune host/elsa --dry-run --keep-daily 1 --keep-weekly 3
+  host/elsa/2019-12-04T13:20:37Z keep
+  host/elsa/2019-12-03T09:35:01Z remove
+  host/elsa/2019-11-22T11:54:47Z keep
+  host/elsa/2019-11-21T12:36:25Z remove
+  host/elsa/2019-11-10T10:42:20Z keep
+
+
 .. note:: Neither the ``prune`` command nor the ``forget`` command free space
    in the chunk-store. The chunk-store still contains the data blocks
    unless you are performing :ref:`garbage-collection`.