title: Getting the date format for grep -E in Unix
body: <p>I write the dates on my file with the next format</p>
  
  <pre><code>date +%a-%b-%d-%Y
  </code></pre>
  
  <p>My goal in my exercise is to get the list of the dates in my file.
  I know I need to do it with <code>grep -E</code>, but I don't know how to put correctly the format of the date.</p>
  
  <p>Desired input:</p>
  
  <pre><code>"grep -E (the format of the dates I'm looking for)" ~/file1
  </code></pre>
  
  <p>Desired output:</p>
  
  <pre><code>Tue-Oct-15-2013
  Wen-Oct-16-2013
  Wen-Oct-16-2013
  Thu-Oct-17-2013
  </code></pre>