diff -r 663fbc336e22 -r 29d29a82263f mercurial/commands.py
--- a/mercurial/commands.py	Sun Sep 06 11:28:48 2015 -0700
+++ b/mercurial/commands.py	Fri Sep 04 11:30:38 2015 -0400
@@ -875,7 +875,7 @@
     [('f', 'force', False, _('force')),
     ('r', 'rev', '', _('revision'), _('REV')),
     ('d', 'delete', False, _('delete a given bookmark')),
-    ('m', 'rename', '', _('rename a given bookmark'), _('NAME')),
+    ('m', 'rename', '', _('rename a given bookmark'), _('OLD')),
     ('i', 'inactive', False, _('mark a bookmark inactive')),
     ] + formatteropts,
     _('hg bookmarks [OPTIONS]... [NAME]...'))
@@ -916,6 +916,10 @@
 
           hg book -r .^ tested
 
+      - rename bookmark turkey to dinner::
+
+          hg book -m turkey dinner
+
       - move the '@' bookmark from another branch::
 
           hg book -f @