title: Can we use local env variable in Docker file COPY command?
body: <p>Can I use host env variable in source part of <code>COPY</code> command in <code>Dockerfile</code>.<br />
  Eg: I have env varianle <code>MY_HOME = /abc/def</code></p>
  <p>Can I use following in Dockerfile?</p>
  <pre><code>COPY ${MY_HOME}/xyz.conf /ams/config/xyz.conf
  </code></pre>