Reclaim Docker claimed disk space on macOS

gistfile1.txt

You can reclaim your host's disk-space on macOS in the new Docker 1.13, reducing the file size of the `Docker.qcow2` file.

Steps:
1. du -sh ~/Library/Containers/com.docker.docker/Data (Check current disk usage)
2. docker run --rm -it --privileged --pid=host walkerlee/nsenter -t 1 -m -u -i -n fstrim /var
3. restart docker (starting it might take a while)
4. du -sh ~/Library/Containers/com.docker.docker/Data

Additional:
* Checkout: docker system prune --help

Source:
* https://github.com/djs55/docker.github.io/commit/b9df8fd2040b245537d27930f08ad326598844ce#diff-3c9e26dd35de8ef996a7a91af7240fd2