title: how do I set up my gcc again
body: <p>I've tried to set up CUDA and XCode on my mac to work together, but it failed.
  During the process I went to <code>/usr/bin/</code> and type:</p>
  
  <p>and typed <code>&gt; sudo rm gcc</code></p>
  
  <p>then <code>&gt; sudo ln -s /opt/local/bin/gcc-4.2 gcc</code></p>
  
  <p>I think I screwed up something because now when I type in </p>
  
  <pre><code>&gt; gcc
  </code></pre>
  
  <p>into the terminal, it says</p>
  
  <pre><code>-bash: gcc: command not found
  </code></pre>
  
  <p>how do I fix it and make the default gcc 4.2?</p>