title: AWS Lambda function loop all files in a s3 bucket
body: <p>For AWS Lambda, I can easily add a s3 object trigger on new objects create event. In other words, any new update/upload file will trigger to run my lambda function.</p>
  
  <h3>Questions</h3>
  
  <ul>
  <li>But how about for the existing files?</li>
  <li>Any method to let Lambda to deal with the previously uploaded files?</li>
  </ul>