title: How to extract URLs from an HTML page in Python
body: <p>I have to write a web crawler in Python. I don't know how to parse a page and extract the URLs from HTML. Where should I go and study to write such a program?</p>
  
  <p>In other words, is there a simple python program which can be used as a template for a generic web crawler? Ideally it should use modules which are relatively simple to use and it should include plenty of comments to describe what each line of code is doing.  </p>