$ docker build --build-arg some_variable_name=a_value
FROM ubuntu:18.04 COPY . /app RUN make /app CMD python /app/app.py
FROM busybox ENV foo /bar WORKDIR ${foo} # WORKDIR /bar ADD . $foo # ADD . /bar COPY \$foo /quux # COPY $foo /quux
# getting base image from ubuntu FROM ubuntu:18.04 RUN apt-get update CMD ["echo", "HEY from docker image"]
