diff --git a/git-rebase.sh b/git-rebase.sh
index 0e9d52a500..9a6d7a4730 100755
--- a/git-rebase.sh
+++ b/git-rebase.sh
@@ -49,7 +49,8 @@ do_merge=
 dotest="$GIT_DIR"/rebase-merge
 prec=4
 verbose=
-diffstat=$(git config --bool rebase.stat)
+diffstat=
+test "$(git config --bool rebase.stat)" = true && diffstat=t
 git_am_opt=
 rebase_root=
 force_rebase=