title: How do I switch back to ruby 1.8.7 from ruby 1.9.2?
body: <p>I have following ruby versions (I'm on linux (Ubuntu))</p>
  
  <pre><code>rvm list
  
     ruby-1.8.7-p302 [ i386 ]
     ruby-1.9.1-p378 [ i386 ]
  =&gt; ruby-1.9.2-p0 [ i386 ]
  </code></pre>
  
  <p>When I do:</p>
  
  <pre><code>sudo rvm --default use 1.8.7
  </code></pre>
  
  <p>My RVM Ruby version changed to:</p>
  
  <pre><code>=&gt; ruby-1.8.7-p302 [ i386 ]
     ruby-1.9.1-p378 [ i386 ]
     ruby-1.9.2-p0 [ i386 ]
  </code></pre>
  
  <p>But it doesnt change my system gem version:</p>
  
  <pre><code>ruby -v
  ruby 1.9.2p0 (2010-08-18 revision 29036) [i686-linux]
  </code></pre>
  
  <p>How to change my system ruby version to 1.8.7?</p>