title: Why the "linenos" option fails to add the line number in Jekyll?
body: <p>I am using jekyll to generate my website.  I want to add a line number column to my code block.  I searched google, and everyone told me to add a "linenos" option to the hightlight tag, but i doesn't work in my case:</p>
  
  <pre><code>{% highlight ruby linenos %}
  def foo():
  puts 'foo'
  end
  {% endhighlight %}
  </code></pre>
  
  <p>The highlight is working well, but the line numbers....</p>
  
  <p>Could you help me with this?  If you want to see the source css/html files, hit <a href="https://github.com/winnieliu/winnieliu-winnieliu.github.com" rel="nofollow">here</a>.</p>
  
  <p>Thanks!</p>
  
  <p>Further checking:</p>
  
  <p>the html generated for this section is :</p>
  
  <pre><code>&lt;div class="highlight"&gt;&lt;pre&gt;&lt;code class="ruby"&gt;
      &lt;span class="k"&gt;def&lt;/span&gt; &lt;span class="nf"&gt;foo&lt;/span&gt;&lt;span class="p"&gt;():&lt;/span&gt;
      &lt;span class="nb"&gt;puts&lt;/span&gt; 
      &lt;span class="s1"&gt;&amp;#39;foo&amp;#39;&lt;/span&gt;
      &lt;span class="k"&gt;end&lt;/span&gt;
  &lt;/code&gt;&lt;/pre&gt;&lt;/div&gt;
  </code></pre>