diff --git a/core/c/mbuild.sh b/core/c/mbuild.sh
index e57fc75b4..16c92a7e9 100755
--- a/core/c/mbuild.sh
+++ b/core/c/mbuild.sh
@@ -1,5 +1,4 @@
-#!/bin/sh
-##/usr/bin/env bash
+#!/usr/bin/env bash
 # Automatic build of so files, ignores failed builds.
 # Place latest gmp tarball in the jbigi dir, and exec this script.