diff --git a/mach b/mach
index 2ff80f6b51d..aa21bcef4f0 100755
--- a/mach
+++ b/mach
@@ -1,14 +1,8 @@
-#!/bin/sh
+#!/usr/bin/env python3
 # This Source Code Form is subject to the terms of the Mozilla Public
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at https://mozilla.org/MPL/2.0/.
 
-# The beginning of this script is both valid shell and valid python,
-# such that the script starts with the shell and is reexecuted with
-# the right python.
-''':' && if [ ! -z "$MSYSTEM" ] ; then exec python "$0" "$@" ; else which python3 > /dev/null 2> /dev/null && exec python3 "$0" "$@" || exec python "$0" "$@" ; fi
-'''
-
 import os
 import sys
 
diff --git a/mach.bat b/mach.bat
index 2e76ecf92bc..d9047a1424b 100644
--- a/mach.bat
+++ b/mach.bat
@@ -1,8 +1,9 @@
 @echo off
+set workdir=%~dp0
 
 where /Q py.exe
 IF %ERRORLEVEL% NEQ 0 (
-  python mach %*
+  python %workdir%mach %*
 ) ELSE (
-  py -3 mach %*
+  py -3 %workdir%mach %*
 )