title: Homebrew on Mac Os 10.10 or 10.11 is not working
body: <p>After installed <a href="http://brew.sh/">Homebrew</a>, when I run any <code>brew ***</code>, I keep getting this error:</p>
  
  <pre><code>Homebrew requires Leopard or higher. For Tiger support, see:
  https://github.com/mistydemeo/tigerbrew
  </code></pre>
  
  <p>My Env: Mac OS 10.10(Yosemite)</p>
  
  <p>I checked the <code>brew.rb</code> source, it has:</p>
  
  <pre><code>if MACOS and MACOS_VERSION &lt; 10.5
    abort &lt;&lt;-EOABORT.undent
      Homebrew requires Leopard or higher. For Tiger support, see:
      http://github.com/sceaga/homebrew/tree/tiger
    EOABORT
  end
  </code></pre>
  
  <p>I have no idea why the Yosemite will trigger this version check.</p>