diff --git a/tools/generate_test_textures.lua b/tools/generate_test_textures.lua
index 2478aac83..aaf687adc 100755
--- a/tools/generate_test_textures.lua
+++ b/tools/generate_test_textures.lua
@@ -1,3 +1,4 @@
+#!/usr/bin/env lua5.1
 dofile("../init.lua")
 
 local _ = { 0 }