title: Why env variables are not created automatically?
body: <p>I am referring <a href="https://docs.docker.com/userguide/dockerlinks/" rel="nofollow">this site</a> to link containers. </p>
  
  <blockquote>
    <p>When two containers are linked, Docker will set some environment variables in the target container to enable programmatic discovery of information related to the source container.</p>
  </blockquote>
  
  <p>This is the line specified in the documentaion. But when i see /etc/hosts i can see entries for both container. But when i run <code>env</code> command, i don't see any port mappings specified in that docker site.</p>