diff --git a/make-tar.txt b/make-tar.txt
index e4e183f..115295d 100644
--- a/make-tar.txt
+++ b/make-tar.txt
@@ -1,3 +1,8 @@
-to create the tar archive:
+#!/bin/sh
 
-tar czf ezmlm-web-2.x.tar.gz --owner=0 --group=0 --exclude=.svn ezmlm-web-2.x
+set -eu
+
+[ $# -ne 1 ] && echo "Syntax: `basename $0` VERSION" && echo && exit 1
+[ ! -d "ezmlm-web-${1}" ] && echo "the directory 'ezmlm-web-${1}' does not exist!" && exit 2
+
+tar czf ezmlm-web-${1}.tar.gz --owner=0 --group=0 --exclude=.svn ezmlm-web-${1}