Docker Command Cheat Sheet

Containers
Images
- Lifecycle
- Info
Registry & Repository
Dockerfile
References

Containers

Lifecycle

docker rename allows the container to be renamed
docker run creates and starts a container in one operation
docker rm deletes a container

Starting and Stopping

docker start starts a container so it is running.
docker stop stops a running container.
docker restart stops and starts a container.
docker kill sends a SIGKILL to a running container.
docker attach will connect to a running container.

Info

docker ps shows running containers.
docker port shows public facing port of container.
docker top shows running processes in container.
docker stats shows containers’ resource usage statistics.
docker ps -a shows running and stopped containers.
docker stats --all shows a running list of containers.

Import / Export

docker cp copies files or folders between a container and the local filesystem.

Executing Commands

docker exec to execute a command in container.

Images

Lifecycle

docker images shows all images.
docker build creates image from Dockerfile.
docker commit creates image from a container, pausing it temporarily if it is running.
docker rmi removes an image.

Info

docker history shows history of image.
docker tag tags an image to a name (local or registry).

Registry & Repository

A repository is a hosted collection of tagged images that together create the file system for a container.

A registry is a host – a server that stores repositories and provides an HTTP API for managing the uploading and downloading of repositories.

Docker.com hosts its own index to a central registry which contains a large number of repositories. Having said that, the central docker registry does not do a good job of verifying images and should be avoided if you’re worried about security.

docker login to login to a registry.
docker logout to logout from a registry.
docker pull pulls an image from registry to local machine.
docker push pushes an image to the registry from local machine.

Dockerfile

The configuration file. Sets up a Docker container when you run docker build on it. Vastly preferable to docker commit.

Here are some common text editors and their syntax highlighting modules you could use to create Dockerfiles:

If you use jEdit, I’ve put up a syntax highlighting module for Dockerfile you can use.
Sublime Text
Atom
Vim
Emacs
TextMate
VS Code
Also see Docker meets the IDE

Instructions

.dockerignore
FROM Sets the Base Image for subsequent instructions.
MAINTAINER (deprecated - use LABEL instead) Set the Author field of the generated images.
RUN execute any commands in a new layer on top of the current image and commit the results.
CMD provide defaults for an executing container.
EXPOSE informs Docker that the container listens on the specified network ports at runtime. NOTE: does not actually make ports accessible.
ENV sets environment variable.
ADD copies new files, directories or remote file to container. Invalidates caches. Avoid ADD and use COPY instead.
COPY copies new files or directories to container. Note that this only copies as root, so you have to chown manually regardless of your USER / WORKDIR setting. See https://github.com/moby/moby/issues/30110
ENTRYPOINT configures a container that will run as an executable.
VOLUME creates a mount point for externally mounted volumes or other containers.
USER sets the user name for following RUN / CMD / ENTRYPOINT commands.
WORKDIR sets the working directory.
ARG defines a build-time variable.
ONBUILD adds a trigger instruction when the image is used as the base for another build.
STOPSIGNAL sets the system call signal that will be sent to the container to exit.
LABEL apply key/value metadata to your images, containers, or daemons.

Tutorial

Flux7’s Dockerfile Tutorial

Examples

References

[1] https://github.com/wsargent/docker-cheat-sheet