title: What is the difference betwwen `Rprofile`,`Renviron` and `Rprofile.site`,`Renviron.site`?
body: <p>In my computer:</p>
  
  <ol>
  <li><p>There are three files in /etc/R
  <code>Renviron</code> and <code>Rprofile.site</code>,<code>Renviron.site</code> ,
  I can not find <code>Rprofile</code> anywhere. Is that a proper status?  </p></li>
  <li><p>What is the difference beetwen <code>Rprofile</code>,<code>Renviron</code> and <code>Rprofile.site</code>,<code>Renviron.site</code>?  </p></li>
  </ol>