diff --git a/git-filter-branch.sh b/git-filter-branch.sh
index 2b8cdba157..aafaf708da 100755
--- a/git-filter-branch.sh
+++ b/git-filter-branch.sh
@@ -239,7 +239,7 @@ git rev-parse --no-flags --revs-only --symbolic-full-name \
 sed -e '/^^/d' "$tempdir"/raw-heads >"$tempdir"/heads
 
 test -s "$tempdir"/heads ||
-	die "Which ref do you want to rewrite?"
+	die "You must specify a ref to rewrite."
 
 GIT_INDEX_FILE="$(pwd)/../index"
 export GIT_INDEX_FILE