title: How can I calculate an MD5 checksum of a directory?
body: <p>I need to calculate a summary MD5 checksum for all files of a particular type (<code>*.py</code> for example) placed under a directory and all sub-directories.</p>
  <p>What is the best way to do that?</p>
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  <p>The proposed solutions are very nice, but this is not exactly what I need. I'm looking for a solution to get a <strong>single summary</strong> checksum which will uniquely identify the directory as a whole - including content of all its subdirectories.</p>