Is it possible to rewrite a subdomain like http://hello.abc.com Into http://www.abc.com?u=hello I have seen people doing this using .htaccess file.
Why would you need to do that ? I don't see where they would use htaccess, however you can do this with php.
No, it can be done using .htaccess It's just like rewriting http://www.abc.com/text/hello into http://www.abc.com?u=hello I want the same effect with sub domain