title: os.walk without hidden folders
body: <p>I need to list all files with the containing directory path inside a folder. I tried to use <code>os.walk</code>, which obviously would be the perfect solution.</p>
  
  <p>However, it also lists hidden folders and files. I'd like my application not to list any hidden folders or files. Is there any flag you can use to make it not yield any hidden files?</p>
  
  <p>Cross-platform is not really important to me, it's ok if it only works for linux (.* pattern)</p>