diff --git a/t/t4128-apply-root.sh b/t/t4128-apply-root.sh
index bc7a8a8689..8f6aea48d8 100755
--- a/t/t4128-apply-root.sh
+++ b/t/t4128-apply-root.sh
@@ -72,7 +72,7 @@ test_expect_success 'apply --directory (delete file)' '
 	echo content >some/sub/dir/delfile &&
 	git add some/sub/dir/delfile &&
 	git apply --directory=some/sub/dir/ --index patch &&
-	! git ls-files | grep delfile
+	! (git ls-files | grep delfile)
 '
 
 cat > patch << 'EOF'