.htaccess Redirect

Hello,
Say I was having some problems with my site and didn't want anyone to see it while I was making changes.
How would I (using .htaccess) redirect every page (except /123.php) to 123.php.

eg.
user goes to: http://www.musicgoeson.com/artists/fgth/
I don't want them to see this page, I want them to see 123.php

How can I do this?

Thanks

Girish Gupta

Let's assume 123.php resides at -> http://www.musicgoeson.com/123.php

Place an .htaccess with the following few lines to http://www.musicgoeson.com/.htaccess

#############################################
RewriteEngine on
RewriteCond %{REQUEST_URI} !^/123.php$
RewriteRule (.*) http://www.musicgoeson.com/123.php [R]
#############################################

The 2nd line means any REQUEST_URI EXCEPT the exact /123.php will follow the rewrite rule

The 3rd line means anything including requesting an image from your site will be redirected to /123.php. So if your 123.php has no images, then you don't have to worry about it.