In some cases you might need to redirect your complete site from www.yoursite.com to yoursite.com , using htaccess on a linux environment with Apache web server this can be achieved with the following directive:

Options +FollowSymLinks
RewriteEngine on
RewriteCond %{HTTP_HOST} ^www.yoursite.com [NC]
RewriteRule ^(.*)$ http://yoursite.com/$1 [L,R=301]

In the opposite case you might need to redirect yoursite.com to www.yoursite.com

The following directive will do it:

Options +FollowSymLinks
RewriteEngine on
RewriteCond %{HTTP_HOST} ^yoursite.com [NC]
RewriteRule ^(.*)$ http://www.yoursite.com/$1 [L,R=301]

For such directives to work make sure htaccess directives are enabled on the apache config.

Cheers
Felipe Cruz