title: AWK - How can I get the values that it equal among them? if ... $1== $1?
body: <p>I am working with a list of DNA sequences. I would like to get all the sequences with the same name ($1). I was thinking to use <code>if ($1 == &quot;$1&quot;)</code>. But this does not work.</p>
  <h3>result_file:</h3>
  <pre>
  name1 number1 number2 sequenceofname1
  name1 number3 number4 sequenceofname1
  </pre>
  <h3>script:</h3>
  <pre><code>awk '{if ($1 == &quot;$1&quot;) printf(&quot;%s_%s_%s \t%s\n&quot;, $1,$2,$3,$4);}' &lt;result_file &gt;file.txt
  </code></pre>
  <p>How do I pass <code>$1</code> to my awk command?</p>