diff --git a/contrib/subtree/git-subtree.sh b/contrib/subtree/git-subtree.sh
index dc59a91031..db925ca769 100755
--- a/contrib/subtree/git-subtree.sh
+++ b/contrib/subtree/git-subtree.sh
@@ -46,6 +46,7 @@ ignore_joins=
 annotate=
 squash=
 message=
+prefix=
 
 debug()
 {