diff --git a/src/drv/mbuf/mbuf_probe/mbuf_probe.cc b/src/drv/mbuf/mbuf_probe/mbuf_probe.cc
index b23dd4e82dfd093f2ae4c86d30eabd127a260725..d3d5080e8f5414e177629e1f732bbfb3ced2d4e2 100644
--- a/src/drv/mbuf/mbuf_probe/mbuf_probe.cc
+++ b/src/drv/mbuf/mbuf_probe/mbuf_probe.cc
@@ -198,7 +198,7 @@ parse_options( int argc, char* argv[] )
         else
         {
             std::map< std::string, MBufCommands >::iterator it;
-            it = command_lookup.find( args.front( ) );
+            it = command_lookup.find( arg );
             if ( it == command_lookup.end( ) )
             {
                 std::ostringstream os;
@@ -374,4 +374,4 @@ main( int argc, char* argv[] )
         break;
     }
     return 0;
-}
\ No newline at end of file
+}