prune: Elaborate on what formats are accepted by dates

Inquiring minds want to know.

Closes: #461
Approved by: giuseppe

diff --git a/man/ostree-prune.xml b/man/ostree-prune.xml
index 9e8cc87300b2dc60b5164cf911da48b3471de099..516da2babc787a5e5157576d3804fc471f590479 100644 (file)
--- a/man/ostree-prune.xml
+++ b/man/ostree-prune.xml
@@ -93,8 +93,11 @@ Boston, MA 02111-1307, USA.
                 <term><option>--keep-younger-than</option>=DATE</term>
 
                 <listitem><para>
-                    All commits older than DATE will be pruned.
-                </para></listitem>
+                 All commits older than DATE will be
+                  pruned.  The format of DATE is the same as that
+                  accepted by GNU <program>date</program> utility - for more information
+                  see <literal>info date</literal>.
+               </para></listitem>
             </varlistentry>
 
             <varlistentry>