How to redirect to www.domain.com in linux?

How di I redirect to www.domain.com when a user access a file in a server without www. ?

I am no开发者_如何学Ct just talking about index.php file.

THanks!

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gruber uses the .htaccess to redirect. read more http://daringfireball.net/2006/05/htaccess_redirection

you could do the inverse.