docker-cp
Copy files or directories between host and container filesystems.
TLDR
Copy a file or directory from the host to a container
$ docker cp [path/to/file_or_directory_on_host] [container_name]:[path/to/file_or_directory_in_container]
Copy a file or directory from a container to the host
$ docker cp [container_name]:[path/to/file_or_directory_in_container] [path/to/file_or_directory_on_host]
Copy a file or directory from the host to a container, following symlinks (copies the symlinked files directly, not the symlinks themselves)
$ docker cp --follow-link [path/to/symlink_on_host] [container_name]:[path/to/file_or_directory_in_container]