In apache, we can redirect pages having no www to its www counterpart without manualy adding the www on the url by using mod_rewrite. Like for example, try to type in my url as tildemark.com on your browser's address bar, hit Enter and automatically you will be redirected to http://www.tildemark.com. This is useful to avoid duplicate caching of pages and the division of your pages' PR.
We need to edit our .htaccess file to add the 301 redirect.
# .htaccess file
# we need to check if mod_rewrite has been enabled,
# by default its not
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{HTTP_HOST} ^tildemark.com
RewriteRule (.*) http://www.tildemark.com/$1 [R=301,L]
</IfModule>
Replace tildemark.com to your respective domain name. here's a mod_rewrite cheatsheet from ilovejackdaniels.com
Notes:
301 is an http status code meaning permanent redirect
.htaccess files should be placed on the root directory
PR is PageRank
