title: htaccess reg ex to add trailing slash to directories but not some drupal aliases
body: <p>I'm very new to reg ex's and have a number of drupal aliases including some legacy .html files (aliases) that I want to retain for SEO reasons. I need to force slashes on virtual directories and force no slashes on .html aliases. </p>
  
  <p>So far I have this code which adds the slashes to directories and not to .html but it still allows a user or agent to go to .html/ - any help rewriting the removal or 404 of this slash greatly appreciated.</p>
  
  <pre><code>RewriteBase /
  RewriteCond %{REQUEST_FILENAME} !-f
  RewriteCond %{REQUEST_FILENAME} !-d
  #is not an htm/l file
  RewriteCond %{REQUEST_URI} !\.html?$ [NC]
  #does not end with a slash
  RewriteCond %{REQUEST_URI} !/$ 
  RewriteRule ^(.+)$ http://www.example.com/$1/ [L,R=301]
  </code></pre>