Using Prune to Keep Your Docker System Clean added

Author: codershona

docker-process-approach/docker-2.md

@@ -239,4 +239,17 @@ docker image rm codersh/testing-node
 docker container run --rm -p 80:3000 codersh/testing-node
 ```
 
+### Using Prune to Keep Your Docker System Clean:
+You can use "prune" commands to clean up images, volumes, build cache, and containers. Examples include:
+```
+docker image prune to clean up just "dangling" images
+
+docker system prune will clean up everything
+```
+ * The big one is usually ```docker image prune -a ``` which will remove all images you're not using. Use docker system df to see space usage.
 
+```
+Remember each one of those commands has options you can learn with --help.
+Here's a YouTube video I made about it: https://youtu.be/_4QzP7uwtvI
+Lastly, realize that if you're using Docker Toolbox, the Linux VM won't auto-shrink. You'll need to delete it and re-create (make sure anything in docker containers or volumes are backed up). You can recreate the toolbox default VM with docker-machine rm default and then docker-machine create
+```