How to redirect url with or without www in htaccess

Normally every website domain is accessible with or without www (mydomain.com or www.mydomain.com). We will get the same pages & there will be no difference. But Google will consider it as duplicated content and it will affect your Search Engine Optimization ranking. So we should define a preferred domain method with the help of htaccess. It will redirect the access to either with or without www. Alternatively, add canonical URL ( <link rel=”canonical” href=”http://www.mydomain.com” /> ) in your page head and don’t forget to choose a preferred domain in Google Webmaster Tools.

Here i’m going to show you how to define a preferred domain method in htaccess.

Redirect mydomain.com to www.mydomain.com:

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

Redirect www.mydomain.com to example.com:

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

Redirect IP to www.example.com:

RewriteEngine on
RewriteCond %{HTTP_HOST} ^12\.34\.56\.789$
RewriteRule ^(.*)$ http://www.mydomain.com/$1 [L,R=301]