title: How can I use grep and regular expression to display names with just 3 characters
body: <p>I am new to grep and UNIX. I have a sample of data and want to display all the first names that only contain three characters e.g. Lee_example.  but I having some difficulty doing that. I am currently using this code  <code>cat file.txt|grep -E &quot;[A-Z][a-z]{2}&quot;</code> but it is displaying all the names that contain at least 3 characters and not <strong>only</strong> 3 characters</p>
  <p>Sample data</p>
  <div class="s-table-container">
  <table class="s-table">
  <thead>
  <tr>
  <th>name</th>
  <th>number</th>
  </tr>
  </thead>
  <tbody>
  <tr>
  <td>Lee_example</td>
  <td>1</td>
  </tr>
  <tr>
  <td>Hector_exaple</td>
  <td>2</td>
  </tr>
  </tbody>
  </table>
  </div>