title: grep using grep results
body: <p>Let's say I have two files containing attribute names and properties, where  different data is stored in two files:</p>
  
  <p><strong>1.txt:</strong></p>
  
  <pre><code>abc12      3@     50
  edf13      4@     50
  dde8       3@     50
  </code></pre>
  
  <p><strong>2.txt</strong></p>
  
  <pre><code>abc12      3@     65
  edf13      4@     50
  dde8       3@     70
  dde7       3@     70
  </code></pre>
  
  <p>I want to grep as follows: 
  first- <code>grep "3@" 1.txt | awk '{print $1}'</code>, then <code>grep * 2.txt</code> where star(*) represent output of first grep.</p>
  
  <p>all should be done in a single line from the prompt.</p>
  
  <p><strong>expected output:</strong></p>
  
  <pre><code>abc12      3@     65
  dde8       3@     70
  </code></pre>
  
  <p>Thanks</p>