The “docker image” command is an essential part of the Docker CLI and is used to manage Docker images. Docker images serve as the building blocks for containers and contain everything needed to run an application, including the operating system, dependencies, and application code.
The “docker image” command provides a set of subcommands that allow users to perform various operations related to managing Docker images. These subcommands enable users to build, pull, push, tag, inspect, and remove Docker images, among other actions.
Here are some commonly used subcommands of the “docker image” command:
- “docker image build“: This subcommand is used to build a Docker image from a Dockerfile, which is a text file that contains instructions on how to build the image. Users can specify the build context, which includes the necessary files and directories required for the image construction.
- “docker image pull“: This subcommand is used to pull a Docker image from a remote registry, such as Docker Hub. If the specified image is not available locally, Docker will retrieve it from the remote registry and store it on the local system.
- “docker image push“: This subcommand is used to push a locally built or pulled Docker image to a remote registry. It allows users to share their custom images with others or deploy them to different environments.
- “docker image tag“: This subcommand is used to add a tag or label to a Docker image. Tags are used to differentiate between different versions or variants of an image. By tagging an image, users can assign it a meaningful name that reflects its purpose or version.
- “docker image inspect“: This subcommand is used to retrieve detailed information about a specific Docker image. It provides metadata about the image, such as its ID, size, creation date, and the layers it consists of.
- “docker image rm“: This subcommand is used to remove one or more Docker images from the local system. It frees up disk space and allows users to manage their local image repository efficiently.
These are just a few examples of the subcommands available under “docker image.” The Docker CLI offers many more options and functionalities to manage images effectively. Users can refer to the official Docker documentation or use the “docker image –help” command to explore the available options and get more information about each subcommand.
docker image Command Examples
1. List local Docker images:
# docker image ls
2. Delete unused local Docker images:
# docker image prune
3. Delete all unused images (not just those without a tag):
# docker image prune --all
4. Show the history of a local Docker image:
# docker image history image
Summary
In summary, the “docker image” command is a powerful tool for managing Docker images. With its various subcommands, users can build, pull, push, tag, inspect, and remove images, among other image-related operations. This command plays a crucial role in the Docker ecosystem, allowing users to create, distribute, and manage the images that serve as the foundation for their containerized applications.