title: Heroku is not passing correct arguments to entrypoint of Docker
body: <p>I want to push a docker image to Heroku and run it with the following ENTRYPOINT inside my Dockerfile:</p>
  <pre><code>ENTRYPOINT [&quot;sh&quot;,&quot;-c&quot;, &quot;/entrypoint.sh --port $PORT&quot;]
  </code></pre>
  <p>Inside entrypoint.sh, I print all the arguments:</p>
  <pre><code>echo &quot;$@&quot;
  
  while [ &quot;$#&quot; -gt 0 ]
    do
      echo &quot;arg1 = $1&quot;
      echo &quot;arg2 = $2&quot;
      case $1 in
        -p|--port)
          PORT=$2
          ;;
      esac
      shift
    done
  
  
  echo $PORT
  </code></pre>
  <p>When I run this locally, I get the result as expected.</p>
  <p>But when I push it to Heroku, I see this in the logs:</p>
  <pre><code> Starting process with command `sh -c /entrypoint.sh\ --port\ \49778`
  </code></pre>
  <p>So I can assume that the --port is correct. But when I echo the $PORT, I get an empty result.</p>
  <p>Can someone please help? Thanks</p>