how to create multiple level subdomains with apache2 and/or PHP

I am looking for a way to have multiple-level subdomains on a server running Apache2.2 and PHP5. Ideally the solution will be in Apache and not PHP.

For instance:

www.apps.example.com OR test.apps.example.com

I've seen this on commercial sites before but have not seen any solutions for how to implement this. I essentially want to allow users to e开发者_如何学运维ither enter www before any subdomain or just to enter the subdomain without the www's. so both x.example.com and www.x.example.com resolve to the same directory.

I am running CentOS 5.4 & Ubuntu 8.04, PHP 5.2.10 & Apache 2.2

Thanks

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You can dynamically add entries into apache config files using a PHP language, But remember you are living on edge of uncertainty

// add this to your httpd.conf
Include extra/httpd-vhosts.conf

// add this to extra/httpd-vhosts.conf
<VirtualHost *:80>
// with www prefix
DocumentRoot /www/example/x
ServerName x.example1.com
ServerAlias www.x.example1.com
</VirtualHost>

<VirtualHost *:80>
// without www prefix
DocumentRoot /www/example/x
ServerName x.example1.com
</VirtualHost>

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You can do that by adding apache virtual hosts. A bunch of great examples can be found here: http://httpd.apache.org/docs/2.0/vhosts/examples.html