title: grep ignore characters in the pattern
body: <p>The pattern comes from a variable of length 14. That string is a pattern to grep. Now the text file has lines that contain 13 characters each.</p>
  
  <p>For example, the pattern of length 14 is</p>
  
  <pre><code>pattern =   58244804671021
  </code></pre>
  
  <p>and the text file contains</p>
  
  <pre><code>3823480467102
  4724470467102
  </code></pre>
  
  <p>How can I make grep ignore the last char in the pattern? </p>