title: How to get only difference from diff
body: <p>I have this code , how to improve it</p>
  
  <pre><code>diff  -b -i -w  out.txt out2.txt  
   | grep '^&gt;' 
   | sed 's/^&gt;//g' 
   | sed ':a;N;$!ba;s/\n/ /g' 
  </code></pre>
  
  <p>example data (out.txt)</p>
  
  <pre><code>abc def ghk
  abc def2 ghk
  abc def ghk
  
  123 333 555
  566 3423 23
  566 3423 3542
  </code></pre>
  
  <p>example data (out2.txt)</p>
  
  <pre><code>abc def2 ghk
  abc def ghk
  abc def ghk
  
  123 555 555
  fsdjhfsda sd
  566 3423 3542
  </code></pre>
  
  <p>expected result :</p>
  
  <pre><code>abc def ghk  123 555 555  fsdjhfsda sd
  </code></pre>