What does the command `docker pull` do?

The command docker pull is used to fetch a Docker image from a remote registry, such as Docker Hub. When this command is executed, Docker communicates with the registry to download the specified image, along with any necessary layers and dependencies that comprise that image. This is essential for users looking to deploy applications using pre-built images or to keep their local images up to date with the latest versions available in the registry.

For instance, when a user runs docker pull nginx, Docker retrieves the latest version of the Nginx image from the Docker Hub repository, making it available to run containers on their local machine.

Understanding this command is crucial for anyone looking to work with Docker effectively, as pulling images is a foundational step in deploying containerized applications.