title: grep is not working as expected
body: <p>i have tried to grep in a file ......
  in file i have 5 entities</p>
  
  <pre><code>vivek
  vivek.a
  a.vivek
  vivek_a
  a_vivek
  </code></pre>
  
  <p>when i grep as <code>grep -iw vivek</code> filename, then it should give me 
  vivek only but it give</p>
  
  <pre><code>vivek
  vivek.a
  a.vivek
  </code></pre>