Run from your command line:
docker version
| Possible result | Explanation |
|---|---|
| bash: docker: No such file or directory | You need to install docker |
| Client: Version: < 1.0.0 | You need a newer version of docker |
| Server: Version: < 1.0.0 | You need a newer version of docker |
| Client: Version: > 1.0.0\nServer: Version: > 1.0.0 | You are all good |
If you need to install docker, start here:
https://docs.docker.com/engine/installation/
Run from your command line:
docker ps
If you see a (possibly empty) list of running containers, you are good.