Index: otf2bdf-3.1/otf2bdf.c
===================================================================
--- otf2bdf-3.1.orig/otf2bdf.c
+++ otf2bdf-3.1/otf2bdf.c
@@ -1283,6 +1283,10 @@ main(int argc, char *argv[])
 
     while (argc > 0) {
         if (argv[0][0] == '-') {
+          if (strchr("lLcCtTwWsSkKdDfFuUpPeErRmMoO", argv[0][1]) && (argc < 2 || !argv[1])) {
+            fprintf(stderr, "%s: command line argument %s requires a parameter.\n", prog, argv[0]);
+            exit(1);
+          } else
             switch (argv[0][1]) {
               case 'v': case 'V':
                 verbose = 1;