title: How do I append to PATH environment variable when running a Docker container?
body: <p>I want to mount a volume and add it to the container's PATH environment variable. I've tried the following and none is working.</p>
  
  <pre><code>docker run -it -v $(PWD):/app -e PATH=$PATH:/app/bin debian:jessie bash
  docker run -it -v $(PWD):/app -e PATH='$PATH:/app/bin' debian:jessie bash
  docker run -it -v $(PWD):/app -e PATH='$$PATH:/app/bin' debian:jessie bash
  docker run -it -v $(PWD):/app -e PATH='\$PATH:/app/bin' debian:jessie bash
  </code></pre>
  
  <p>How do I append the mounted volume to PATH?</p>