title: unzip a tar.gz file?
body: <p>I wish to download and open the following <code>tar.gz</code> file in R:</p>
  
  <p><a href="http://s.wordpress.org/resources/survey/wp2011-survey.tar.gz" rel="noreferrer">http://s.wordpress.org/resources/survey/wp2011-survey.tar.gz</a></p>
  
  <p>Is there a command which can accomplish this?</p>