diff --git a/DEVEL/Developer.txt b/DEVEL/Developer.txt
index 7c4fa4908..142dc7f6a 100644
--- a/DEVEL/Developer.txt
+++ b/DEVEL/Developer.txt
@@ -61,6 +61,8 @@ B. Specify the prefix for variable substitution:
 	the first line):
 		#!/bin/sh
 		git config nethack.substprefix MINE
+	Now make it executable:
+		chmod +x ~/nethack/GITADDDIR/DOTGIT/PRE
 C. Configure the repository:
 	- cd to the top level of the repository
 	- tell the repository about the directory you created above: