I just realized I was using this to redirect non-www to www.
RewriteCond %{HTTP_HOST} !^www\.url\.com$ [NC]
RewriteRule ^(.*)$ http://www.url.com/$1 [R=301,L]
It works, but shouldn't this be the proper way?
RewriteCond %{HTTP_HOST} ^example\.com
RewriteRule (.*) http://www.example.com/$1...