title: Is it possible to output any or all available variables in a .htaccess file?
body: <p>I'm trying to a build a .htaccess file with some rewrite rules and would like to know what several variables actually contain when my request is handled.  Is there anyway of seeing what their values would be when Apache handles the request?</p>
  
  <p>E.g. print the contents of <code>%{HTTP_USER_AGENT}</code></p>