title: RVM doesn't switch Rubies
body: <p>I'm running Ruby 1.9.1p243 on CentOS, and I decided to install rvm to handle upgrading to 1.9.2 or downgrading to 1.8.7 (whichever turns out to work better for rails3).</p>
  
  <p>I followed the instructions here: <a href="http://rvm.beginrescueend.com/rvm/install/" rel="noreferrer">http://rvm.beginrescueend.com/rvm/install/</a> and everything installed correctly. I was able to compile and install Ruby 1.8.7, 1.9.1, and 1.9.2.</p>
  
  <p>However, if I try to actually switch to one of the rvm installed Rubies, with rvm use 1.8.7, for example, nothing works. My system still uses the Ruby I have installed in /usr/local/bin/ruby.</p>
  
  <p>An example of the output I get:</p>
  
  <pre><code>$ rvm use 1.8.7
  $ ruby -v
  ruby 1.9.1p243 (2009-07-16 revision 24175) [i686-linux]
  $ which ruby
  /usr/local/bin/ruby
  $ rvm use 1.9.2
  $ ruby -v
  ruby 1.9.1p243 (2009-07-16 revision 24175) [i686-linux]
  $ which ruby
  /usr/local/bin/ruby
  </code></pre>
  
  <p>I have no idea why this is happening, and I can't seem to find anything online about the issue either. Any help would be appreciated.</p>