diff --git a/doc/git-annex-group.mdwn b/doc/git-annex-group.mdwn
index 3b6bac109a..8a7455d82f 100644
--- a/doc/git-annex-group.mdwn
+++ b/doc/git-annex-group.mdwn
@@ -4,7 +4,7 @@ git-annex group - add a repository to a group
 
 # SYNOPSIS
 
-git annex group `repository groupname`
+git annex group `repository [groupname]`
 
 # DESCRIPTION