LocalSettings.php allowing multiple MW instances in the same directory

awiki.py

#! /usr/bin/python
import re, os, readline, sys
input = raw_input if sys.version_info.major == 2 else input
choices = []
for f in os.listdir('settings'):
    if re.match(r'^[a-z]+\.php', f):
        choices.append(f.replace('.php', ''))

def set_wiki(wiki):
    if wiki in choices:
        with open('active_wiki.txt', 'w') as f:
            f.write(wiki)
        return True
    return False

first = True
while True:
    for arg in sys.argv[1:]:
        if set_wiki(arg):
            sys.exit()
    if first:
        first = False
        print('Available wikis:')
        for wiki in choices:
            print('* %s' % wiki)
    wiki = input('Select active wiki: ')
    if set_wiki(wiki):
        sys.exit()

Multiwiki.php

<?php
namespace Localsettings_switch;
$wikis = array();  // Add wikis to this array, corresponding to settings file - e.g. "test" should have its settings in settings/test.php
$activeWiki = preg_replace('/[^a-z]/', '', @file_get_contents(__DIR__ . '/active_wiki.txt'));
$settings = __DIR__ . "/settings/$activeWiki.php";
if (in_array($activeWiki, $wikis) && file_exists($settings)) {
	require_once $settings;
}
else {
	$wikis = implode("</li>\n<li>", $wikis);
	$help = <<<END
<h1>Error</h1>
<p>The specified wiki ("$activeWiki") is not valid. Possible reasons:</p>
<ol>
<li>active_wiki.txt is empty or does not refer to a valid wiki</li>
<li>You forgot to add the specified wiki to \$wikis in LocalSettings.php</li>
<li>The wiki's settings file does not exist</li>
</ol>
<h2>Valid wikis are:</h2>
<ul><li>$wikis</li></ul>
END;
	if (php_sapi_name() == 'cli') $help = strip_tags($help);
	die($help);
}

require_once(__DIR__ . '/settings/_common.php');

"Multiwiki.php" should be renamed to "LocalSettings.php"