Docker - how can I copy a file from an image to a host?

Question

My question is related to this question on copying files from containers to hosts; I have a Dockerfile that fetches dependencies, compiles a build artifact from source, and

Answer 1

Another (short) answer to this problem:

docker run -v $PWD:/opt/mount --rm -ti image:version bash -c "cp /source/file /opt/mount/"

Update - as noted by @Elytscha Smith this only works if your image has bash built in