title: Docker run Python File on startup
body: <p>First of all, I'm very new to Docker, so if my general idea of how this should work is stupid, then please tell me :)
  I created a Dockerfile which looks like this:</p>
  <pre><code>FROM nodered/node-red:1.2.1
  COPY./retrieveNewFlow.py /home/retrieveNewFlow.py
  ENTRYPOINT [ &quot;/bin/bash&quot; ]
  CMD [ &quot;python3&quot;, &quot;/home/retrieveNewFlow.py&quot; ]
  </code></pre>
  <p>I want to execute the retrieveNewFlow.py Python Script every time the container starts. But I get the following error message:</p>
  <pre><code> /usr/bin/python3: /usr/bin/python3: cannot execute binary file
  </code></pre>
  <p>Can anybody image what i've done wrong?</p>