Which command is used to copy files from the host machine to a running container?

The command used to copy files from the host machine to a running container is "docker cp." This command allows users to specify the source path on the host and the destination path inside the container, enabling seamless transfer of files between the two environments. The utility of this command lies in its ability to facilitate file management within containers, which may not have direct access to the host's filesystem, thus enhancing the flexibility of container operations.

In contrast to other commands, "docker cp" directly deals with file transfers, making it a straightforward and effective solution for moving files. The other options do not exist in Docker's command set for this purpose. For instance, there is no "docker send" or "docker transfer" command associated with file transfer functionalities, and "docker pull" is specifically designed for downloading Docker images from a registry, not copying files to a running container.