diff -Naur advi-1.7.3.orig/src/gs.ml advi-1.7.3/src/gs.ml
--- advi-1.7.3.orig/src/gs.ml	2007-11-16 18:12:19.000000000 +0300
+++ advi-1.7.3/src/gs.ml	2009-11-07 05:28:33.000000000 +0300
@@ -140,7 +140,7 @@
     [|
       "-q";
       if !delaysafer then "-dDELAYSAFER" else "-dSAFER";
-      "-";
+      " ";
     |]] in
 
   let _ = debugs command;