title: /usr/bin/gem:8:in `require': no such file to load -- rubygems
body: <p>I install and uninstall ruby 1.8 and 1.9, and install again, and now i am lost...</p>
  
  <p>The 'gem' doesn't work...
  This is the only message i get: </p>
  
  <blockquote>
    <p>/usr/bin/gem:8:in `require': no such file to load -- rubygems (LoadError)<br>
      from /usr/bin/gem:8</p>
  </blockquote>
  
  <p>gem -v - give back the same result</p>
  
  <hr>
  
  <p>Description:    Ubuntu 10.04.4 LTS</p>
  
  <p>which ruby:<br>
  /usr/bin/ruby</p>
  
  <p>which gem<br>
  /usr/bin/gem</p>
  
  <p>ruby -v<br>
  ruby 1.8.7 (2010-01-10 patchlevel 249) [x86_64-linux]</p>
  
  <p>apt-get install rubygems<br>
  rubygems is already the newest version.</p>
  
  <p>rails -v<br>
  getopt: invalid option -- 'v'<br>
  Terminating...</p>