title: Extract only whole word using grep
body: <p>I've got a big text file. I need to extract all the lines which contains the exact word "DUSP1". 
  Here an example of the lines:</p>
  
  <pre><code>9606    ENSP00000239223 DUSP1   BLAST
  9606    ENSP00000239223 DUSP1-001 Ensembl
  </code></pre>
  
  <p>I want to retrieve the first line but not the second one.</p>
  
  <p>I tried several commands as:</p>
  
  <pre><code>grep -E "^DUSP1"
  grep '\&lt;DUSP1\&gt;'
  grep '^DUSP1$'
  grep -w DUSP1
  </code></pre>
  
  <p>But none of them seem to work. Which option should I use?</p>