title: Difference between 2 regex using egrep
body: <p>I wanna know what is the difference between:</p>
  
  <pre><code>sudo egrep "(08/21/13\-)*(61284103)" /path/to/some_file
  sudo egrep "(08/21/13)\-*(61284103)" /path/to/some_file
  </code></pre>
  
  <p>Lets say that for details, the file "some_file" has the next info:</p>
  
  <pre><code>08/21/13-01:15:09 foo bar bar and other foo = 11 (61284103)
  08/21/13-01:15:11 foo bar number 61284103 another foo
  </code></pre>
  
  <p>The first one returns the both lines, however the second one doesn't work.</p>