diff --git a/xdu.c b/xdu.c
index 3c21373..747ce68 100644
--- a/xdu.c
+++ b/xdu.c
@@ -215,7 +215,7 @@ char **argv;
     xsetup(&argc, argv);
     if (argc == 1) {
         if (isatty(fileno(stdin))) {
-            fprintf(stderr, usage);
+            fprintf(stderr, "%s", usage);
             exit(1);
         } else {
             parse_file("-");
@@ -223,7 +223,7 @@ char **argv;
     } else if (argc == 2 && strcmp(argv[1], "-help") != 0) {
         parse_file(argv[1]);
     } else {
-        fprintf(stderr, usage);
+        fprintf(stderr, "%s", usage);
         exit(1);
     }
     top.size = fix_tree(&top);
@@ -885,6 +885,7 @@ void savepsnode(FILE * fp, struct node *nodep, struct rect rect, int showsize)
         name = label;
         break;
     default:
+	name = NULL;
         break;
     }