title: How to list all folders and files recursively?
body: <p>How can I get folders and files <strong>including</strong> files/folders of subdirectories in python?
  I need the absolute path of each file/folder.</p>
  
  <p>I want to rename all folders and files. So I have to rename the folders first.</p>
  
  <pre><code>folder
  -- file
  -- folder1
  ---- folder1.1
  ------ file
  ------ folder1.1.1
  -------- file
  -- folder2
  ---- ...
  </code></pre>