title: How to get back into shell started with docker exec?
body: <p>If you start a new shell in a container with <code>docker exec</code>, then exit with ctrl+p ctlr+q, that shell is still running. However if you use <code>docker attach</code> it attaches to the shell at PID 1, not the one started with docker exec. How do you get back into it? If there's no way to get back into it, then when would you ever exit and leave it running like this?</p>