diff -uNr robodoc-4.99.43/Source/robohdrs.c robodoc-4.99.43-new/Source/robohdrs.c
--- robodoc-4.99.43/Source/robohdrs.c	2015-04-12 01:28:57.000000000 +0800
+++ robodoc-4.99.43-new/Source/robohdrs.c	2021-09-30 14:11:50.969300297 +0800
@@ -289,7 +289,7 @@
     int                 ch;
     custhdr_t          *c, *nc;
 
-    while ( ( ch = getopt( argc, argv, "i:l:p:st:x:" ) ) != -1 )
+    while ( ( ch = getopt( argc, argv, "hi:l:p:st:x:" ) ) != -1 )
         switch ( ch )
         {