Redirecting through .htaccess

[knkk]

I want to redirect a url http://abc.xyz.com/123 to http://www.xyz.com. So the file that will be accessed will be index.php of xyz.com. That index.php should have available to it both abc and 123 (so 123 will be $_SERVER['PHP_SELF'], and abc will come out of $_SERVER['HTTP_HOST']) to enable appropriate processing.

http://abc.xyz.com already goes to http://www.xyz.com (though configuration by my service provider), and abc can be extracted out of $_SERVER['HTTP_HOST']. However, http://abc.xyz.com/123 seems to be looking for a folder called 123 in the root directory of xyz.com, and is showing up a 404 error when it cannot find any.

Can someone kindly give me the line(s) to be put in .htaccess to enable http://abc.xyz.com/123 to call index.php of http://www.xyz.com (with 123 being available though $_SERVER['PHP_SELF']? I cannot seem to get it to work.

Thank you very much for your time!

[knkk]

I found the solution for my subdomain subdirectory redirection problem above, here it is:

Options +FollowSymLinks
RewriteEngine on
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URL} !=/favicon.ico
RewriteRule ^(.*)$ index.php?q=$1 [L,QSA]