Добавить www к домену

Добавляем в .htaccess:

RewriteEngine On
RewriteCond %{HTTP_HOST} ^devreadwrite.com [NC]
RewriteRule ^(.*)$ http://www.devreadwrite.com/$1 [L,R=301]

Убрать www

Добавляем в .htaccess:

RewriteEngine On
RewriteCond %{HTTP_HOST} !^devreadwrite.com$ [NC]
RewriteRule ^(.*)$ http://devreadwrite.com/$1 [L,R=301]