Question

I want to allow the users to type

xyz.example.com

in order to reach

test.php?id=xyz

What code should I use to accomplish my goal?

Answer 1

Try adding the following to your htaccess file in the root directory of your example.com domain

RewriteEngine on
RewriteBase /

#if the host is anything.example.com
RewriteCond %{HTTP_HOST} ^([^\.]+)\.example\.com$ [NC]
#send all requests to test.php
RewriteRule .* test.php?id=%1 [L]