title: Why no output is shown when using grep twice?
body: <p>Basically I'm wondering why this doesn't output anything:</p>
  
  <pre><code>tail --follow=name file.txt | grep something | grep something_else 
  </code></pre>
  
  <p>You can assume that it should produce output I have run another line to confirm</p>
  
  <pre><code>cat file.txt | grep something | grep something_else
  </code></pre>
  
  <p>It seems like you can't pipe the output of tail more than once!? Anyone know what the deal is and is there a solution?</p>
  
  <p>EDIT:
  To answer the questions so far, the file definitely has contents that should be displayed by the grep. As evidence if the grep is done like so:</p>
  
  <pre><code>tail --follow=name file.txt | grep something
  </code></pre>
  
  <p>Output shows up correctly, but if this is used instead:</p>
  
  <pre><code>tail --follow=name file.txt | grep something | grep something
  </code></pre>
  
  <p>No output is shown.</p>
  
  <p>If at all helpful I am running ubuntu 10.04</p>