title: Docker not running/showing long-running processes
body: <p>Why does this occur?</p>
  
  <pre><code>$ docker pull ubuntu
  # stuff...
  $ docker run ubuntu apt-get install -y tree
  Reading package lists...
  $ 
  </code></pre>
  
  <p>It <em>appears</em> to die. <code>$?</code> is 0 though. I have a similar issue with ping:</p>
  
  <pre><code>$ docker run ubuntu ping 8.8.8.8
  PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
  64 bytes from 8.8.8.8: icmp_req=1 ttl=61 time=24.2 ms
  ^C
   $ 
  </code></pre>
  
  <p>Note that ping doesn't dump its usual information about lost packets on ^C.  </p>
  
  <p>Leaving the ping on for a few minutes doesn't result in a sudden dump of text (like I expect when a buffer is flushed).</p>
  
  <p>What is happening here? </p>