diff --git a/src/nghttp.cc b/src/nghttp.cc
index f21dee4f..ef120572 100644
--- a/src/nghttp.cc
+++ b/src/nghttp.cc
@@ -2791,7 +2791,7 @@ int main(int argc, char **argv) {
         {"encoder-header-table-size", required_argument, &flag, 14},
         {nullptr, 0, nullptr, 0}};
     int option_index = 0;
-    int c = getopt_long(argc, argv, "M:Oab:c:d:gm:np:r:hH:vst:uw:yW:",
+    int c = getopt_long(argc, argv, "M:Oab:c:d:m:np:r:hH:vst:uw:yW:",
                         long_options, &option_index);
     if (c == -1) {
       break;