copy file from docker container to host
docker cp <containerId>:/file/path/within/container /host/path/target
copy file from host to docker container
docker cp foo.txt mycontainer:/foo.txt
dockerfile example
FROM ubuntu:18.04
COPY . /app
RUN make /app
CMD python /app/app.py
docker ARG
$ docker build --build-arg some_variable_name=a_value
dockerfile copy specific files
COPY ["__BUILD_NUMBER", "README.md", "gulpfile", "another_file", "./"]
All the files and folders, the last is destination
dockerfile run app cmd
RUN apt-get install python3
CMD echo "Hello world"
ENTRYPOINT echo "Hello world"