docker cli cheat sheet


  • docker COMMAND --help

Images – base of containers

  • Create: docker build -t my-web docker/webserver
    • -t ... name (e.g. my-web) and optionally tag (e.g. my-web:latest, my-web:1.0)
    • docker/webserver ... the dir in which the Dockerfile resides
  • List all: docker images
  • List all with intermediates: docker images -a
  • List specific: docker images my-web
    • Lists versions (i.e. tags) of specific image name (i.e. repository)
  • Delete: docker rmi my-web
    • Attention: Image must not be used by a container

Containers – do the actual work

  • List running: docker ps
  • List all: docker ps -a
  • Remove: docker rm <container-name> or docker container rm <container-name>

Volumes – where containers put their data

  • List all: docker volumes or docker volume ls
  • Remove: docker volume rm <volume-name>


  • How to spare disk space?

    • As much and as little as needed.
  • docker builder prune ... removes dangling build cache

    • Note: Asks for confirmation
    • Removes dangling build cache which are all layers that are not used in any tagged image (I suppose)
  • docker builder prune -a ... removes all build cache

    • Note: Asks for confirmation

Understanding docker build cache

How to enforce a rebuild of a layer?

  • E.g. How to enforce a fresh run of apt update?
  • docker build prune -a
  • docker rmi image-id <-- won't work because it has dependent child images most likely
  • Temporarily add a layer before the RUN apt update -> not working either because if I understand docker build cache correctly, this would run and build a fresh layer. However, when removing that temporary layer before, the "old" aka already cached apt update layer would be used again. So it is going to be docker build prune -a. Well, even that didn't work. Then removing container, image and so forth didn't work either. The cached layer was still somewhere in use. Last remedy was to docker pull ubuntu:20.04 (the base image). What was the problem even? apt-repo mirrors weren't reachable anymore (IP address was not reachable or something like that).
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