wtf? You don't put stuff in your htaccess for fun
You only edit/add to your htaccess file if you need to. So you gotta tell us what you're trying to achieve.

Redirecting root to subdirectory is easy. Just place an index.html file in your root directory and put this in it:
Code: 
<meta http-equiv="refresh" content="0;http://domain.com/subdirectory" />