title: run multiple commands in docker container start
body: <p>I have a simple docker image running on ubuntu 16.04 based on a dockerfile which CMD is <code>"/sbin/ejabberdctl foreground"</code>. to keep the docker container alive once it started I used to run ejabberd server in foreground. However after starting the container and <code>/sbin/ejabberdctl</code> I need to execute another command once ejabberdctl is already running (e.g. <code>ejabberdctl list_cluster</code>).
  Tried to add both commands to bash script, but it doesn't work. tried to run <code>/sbin/ejbberdctl start &amp;</code>, it didn't work either.
  Which way to dig?</p>