diff --git a/umount.c b/umount.c
index 514063d..2b0c32e 100644
--- a/umount.c
+++ b/umount.c
@@ -8,7 +8,9 @@
 static void
 usage(void)
 {
-	eprintf("usage: %s [-alfn] target\n", argv0);
+	weprintf("usage: %s [-lfn] target\n", argv0);
+	weprintf("usage: %s -a [-lfn]\n", argv0);
+	exit(EXIT_FAILURE);
 }
 
 int