How do I copy data to each other inside and outside the Docker container?

Copy files from the container to the host

docker cp <containerId>:/file/path/within/container /host/path/target

Copy files from the host to the container

1. Mount the host data volume into the container with -ES11en

docker run -v /path/to/hostdir:/mnt $container

Copy in the container

cp /mnt/sourcefile /path/to/destfile

2. Copy directly to the container physical storage system on the host

A. Gets the container name or id:

$ docker ps

B. Gets id for the entire container

$ docker inspect -f '{{.Id}}'  steps A Gets the name or id

C. Copy file on host:

$ sudo cp path-file-host /var/lib/docker/aufs/mnt/FULL_CONTAINER_ID/PATH-NEW-FILE 

or

$ sudo cp path-file-host /var/lib/docker/devicemapper/mnt/123abc<<id>>/rootfs/root

Example:

$ docker ps

CONTAINER ID  IMAGE COMMAND  CREATED  STATUS  PORTS  NAMES

d8e703d7e303 solidleon/ssh:latest  /usr/sbin/sshd -D      cranky_pare

$ docker inspect -f '{{.Id}}' cranky_pare

or
$ docker inspect -f '{{.Id}}' d8e703d7e303

d8e703d7e3039a6df6d01bd7fb58d1882e592a85059eb16c4b83cf91847f88e5

$ sudo cp file.txt /var/lib/docker/aufs/mnt/**d8e703d7e3039a6df6d01bd7fb58d1882e592a85059eb16c4b83cf91847f88e5

3. Use I/O

docker run -i ubuntu /bin/bash -c 'cat > /path/to/container/file' < /path/to/host/file/

or

docker exec -it <container_id> bash -c 'cat > /path/to/container/file' < /path/to/host/file/