Docker: Get hold of output files in host directory


I am running a code which produces multiple files as an output. The code is run inside a docker container. In order to access the output files, I tried to mount the host directory in the container using

docker run -v /home/my_username/code_directory/output:/code_directory/output container_name

However, after docker run finished, the output directory is still empty. What am I missing here?

Edit: I am using the image ubuntu:trusty

Source: Docker Questions