diff --git a/Makefile b/Makefile
index 185d8e59..640dd639 100644
--- a/Makefile
+++ b/Makefile
@@ -46,7 +46,7 @@ test: test_format test_dirs test_files test_seek test_truncate \
 test_%: tests/test_%.sh
 
 ifdef QUIET
-	@./$< | sed -n '/^[-=]/p'
+	@./$< | sed -nu '/^[-=]/p'
 else
 	./$<
 endif