title: How to specify lib directory when installing development version R Packages from github repository
body: <p>In Ubuntu, I am installing all the R packages in the directory, <code>/usr/lib/R/site-library</code> by specifying <code>lib</code> option in <code>install.packages()</code>. </p>
  
  <p>But when I try to install the development version of the R packages using, <code>install_github()</code>, it always installs in a local repository of the system user. </p>
  
  <p><code>.libPaths()</code> has 4 directories including the local repository. So, I have 2 questions,</p>
  
  <ol>
  <li><p>Will it install in any of the other 3 repositories if i remove the local repository from <code>.libPaths()</code>?</p></li>
  <li><p>Is there any way to specify installation library path in <code>install_github()</code>?</p></li>
  </ol>
  
  <p>I am using <code>Ubuntu 12.04 64bit</code> and <code>R 3.0.1</code></p>
  
  <p>----------------------UPDATE--------------------------------</p>
  
  <ol>
  <li><p>Unable to remove the local repository from <code>.libPaths()</code></p></li>
  <li><p>If I try to install using <code>install_github()</code> in <strong>RStudio</strong>, it installs in the <code>local repository</code> since <code>lib</code> is not specified.</p></li>
  <li><p>If I try to install using <code>install_github()</code> as <strong>non-root user</strong>, it installs in the <code>local repository</code> since <code>lib</code> is not specified.</p></li>
  <li><p>If I try to install using <code>install_github()</code> as <strong>root user</strong>, it installs in the <code>/usr/local/lib/R/site-library</code> since <code>lib</code> is not specified.</p></li>
  </ol>
  
  <p>Is there any to specify <code>installation lib</code>?</p>