--- a/man/texinfo2man.c
+++ b/man/texinfo2man.c
@@ -287,6 +287,13 @@
    char buf[1024];
    int line_no = 0;
 
+   if (argc != 3)
+   {
+      fprintf(stderr, "Usage: %s <man template> <info file>\n", argv[0]);
+      fprintf(stderr, "  The man page will be written to stdout.\n");
+      return -1;
+   }
+
    texinfoname = argv[2];
 
    in = fopen (argv[2], "r");