docker

# To start the docker daemon:
docker -d

# To start a container with an interactive shell:
docker run -ti <image-name> /bin/bash

# To "shell" into a running container (docker-1.3+):
docker exec -ti <container-name> bash

# To inspect a running container:
docker inspect <container-name> (or <container-id>)

# To get the process ID for a container:
docker inspect --format {{.State.Pid}} <container-name-or-id>

# To list (and pretty-print) the current mounted volumes for a container:
docker inspect --format='{{json .Volumes}}' <container-id> | python -mjson.tool

# To copy files/folders between a container and your host:
docker cp foo.txt mycontainer:/foo.txt

# To list currently running containers:
docker ps

# To list all containers:
docker ps -a

# To list all images:
docker images