Master Docker: Essential Commands for Images, Containers, and Management

Docker image vs images

The docker images command lists available images and can be used directly, whereas docker image is a parent command that requires sub‑commands such as ls to display images.

# docker images
REPOSITORY   TAG       IMAGE ID       CREATED       SIZE
busybox      latest    a9d583973f65   2 years ago   1.23MB
nginx        latest    298ec0e28760   2 years ago   133MB

# docker image
Usage:  docker image COMMAND
Manage images
Commands:
  build   Build an image from a Dockerfile
  history Show the history of an image
  import  Import the contents from a tarball to create a filesystem image
  inspect Display detailed information

# docker image ls   (alias for docker images)

docker pull

Pulls a specified image from a registry to the local host.

# docker pull alpine
Using default tag: latest
latest: Pulling from library/alpine
ca3cd42a7c95: Pull complete
Digest: sha256:e103c1b4bf019dc290bcc7aca538dc2bf7a9d0fc836e186f5fa34945c5168310
Status: Downloaded newer image for alpine:latest
docker.io/library/alpine:latest

docker save

Saves a local image to a tar archive file.

# docker save busybox > busybox.tar
# ls
busybox.tar

docker load

Loads an image from a tar archive created by docker save.

# docker load -i busybox.tar
2983725f2649: Loading layer   1.45MB/1.45MB
Loaded image: busybox:latest

docker rmi

Removes one or more images from the local Docker registry.

# docker images
REPOSITORY   TAG       IMAGE ID       CREATED       SIZE
alpine       latest    49f356fa4513   2 years ago   5.61MB
busybox      latest    a9d583973f65   2 years ago   1.23MB
nginx        latest    298ec0e28760   2 years ago   133MB
# docker rmi alpine
Untagged: alpine:latest
Untagged: alpine@sha256:e103c1b4bf019dc290bcc7aca538dc2bf7a9d0fc836e186f5fa34945c5168310
Deleted: sha256:49f356fa4513676c5e22e3a8404aad6c7262cc7aaed15341458265320786c58c
Deleted: sha256:8ea3b23f387bedc5e3cee574742d748941443c328a75f511eb37b0d8b6164130

docker run

Creates and starts a new container from an image. Common flags:

-t : Allocate a pseudo‑TTY.

-i : Keep STDIN open (interactive).

-d : Run container in detached (background) mode.

# docker run -itd nginx
4c45f7885e579bbbdc795a1489585cad989558c19e832e94dce4dab48b7ea69c

docker start / docker stop

Starts a stopped container or stops a running one.

# docker stop bold_shockley
bold_shockley

docker ps

Lists containers. Without options, only running containers are shown; use -a to list all containers.

# docker ps
CONTAINER ID   IMAGE   COMMAND   CREATED   STATUS   PORTS   NAMES

# docker ps -a
CONTAINER ID   IMAGE   COMMAND                  CREATED         STATUS                     PORTS   NAMES
4c45f7885e57   nginx   "/docker-entrypoint.…"   8 minutes ago   Exited (0) 3 minutes ago           bold_shockley