I discovered another use for this script, by the way.
While I am adamant about the fact that the two files it uses ought to be deleted outright and NOT left on a live server -- the potential exists for this to be used for on the fly moving of your install.
what would need to be done:
1. rename the main script file to something other than emergency-url-change.php This is done just to prevent the casual person poking around looking for it. For purposes of this example, rename it to changer.php
There's no need to rename the config file though you could do that as well, just making sure to change the line inside the other file that looks for it.
2. Lets assume you have your blog installed wordpress/ and lets say you want your blog installed into blog/ but you want to keep the database stuff in tact.
3. You use an ftp client to access your site, you rename the wordpress directory to blog
4. Open the renamed file in your browser, taking care to to remember that the file is now inside blog/ so like you might use:
http://www.domain.com/blog/changer.php
At that point you can change your 2 settings.
--
two weeks later, you decide you want to move your install again.. do the same thing.
This works perfectly as long as you arent looking at changing the database and you are simply moving around within your own site.
It could also be done moving from a subdirectory to your web root..
You just move all the files, including the 2 script files to the root of your site.