How to check if the docker engine and a docker container are running?

Question

In a script, I need to check:

a) Is the docker engine running?
b) Given a container name, is that docker container running?

[the initial wording of this

Answer 1

Run this command in the terminal:

docker ps

If docker is not running, you wil get this message:

Error response from daemon: dial unix docker.raw.sock: connect: connection refused