title: Docker RUN persist environment variables?
body: <pre><code>FROM bitnami/minideb:latest
  
  RUN . /etc/os-release
  RUN echo "code1=${VERSION_CODENAME}"
  RUN . /etc/os-release &amp;&amp; echo "code2=${VERSION_CODENAME}"
  </code></pre>
  
  <p>When I run this, it prints:</p>
  
  <pre><code>code1=
  code2=buster
  </code></pre>
  
  <p>Is there some way to persist the environment variables between RUN commands and/or a separate command to load environment variables from a file <em>inside</em> the container?</p>