Getting data from crashed docker container
So what you can do is you list all of your containers with command:

docker container ls -a


And the second field is an image name, you can run this command to get all the read-only layers with their respective directories to search for the file in:

docker image inspect &lt;image_id&gt; | jq '.[0].GraphDriver.Data.LowerDir' -r | tr ":" "\n"


If the file was something written inside the container replace Lower with Upper. 

In case you are on Mac the /var/lib/docker is inside the virtual machine and so you have to first enter that before you can get to those directories described in the command above. You can do it using nsenter like this:

docker run -it --privileged --pid=host debian nsenter -t 1 -m -u -n -i sh