Docker and Podman Cheatsheet

Short recipes for everyday container work. Podman accepts the same commands, so you can replace docker with podman in any example below.

List Containers

Show running containers, or add -a to include stopped ones:

docker ps
docker ps -a

Open a Shell in a Running Container

Start an interactive shell inside an existing container by name or ID:

docker exec -it <CONTAINER> bash

Minimal images (Alpine, distroless, BusyBox) often have no bash, so fall back to sh. Add --user root if the image runs as an unprivileged user and you need to install tools:

docker exec -it --user root <CONTAINER> sh

Follow a Container's Logs

Stream the last 100 lines of output and keep following:

docker logs -f --tail 100 <CONTAINER>

Copy Files In or Out

Copy a file between the host and a container (running or stopped):

docker cp <CONTAINER>:/path/in/container ./local-copy
docker cp ./local-file <CONTAINER>:/path/in/container

Pull the Latest Version of Every Local Image

Re-pull every tagged image on the host:

docker images --format '{{.Repository}}:{{.Tag}}' | grep -v '<none>' | while read -r image; do
  docker pull "$image"
done

Update a Compose Stack

Pull new images and recreate only the containers whose image changed:

docker compose pull
docker compose up -d

Update Podman Containers Automatically

Podman can update containers that run as systemd services (Quadlet units or podman generate systemd). Label the container with io.containers.autoupdate=registry, then check for or apply updates:

podman auto-update --dry-run
podman auto-update

Enable podman-auto-update.timer to run this daily.

Clean Up Unused Images and Containers

Remove dangling images left behind by updates, or everything not used by a container:

docker image prune
docker system prune