FROM: It defines the build image to start the build process. It’s the fist command declared inside the Dockerfile.
FROM ubuntu
MAINTAINER: Author details of the docker file
RUN: It takes the command as argument and runs it from the base image. Execute during build process.
RUN: apt-get install git
EXPOSE: It uses to enable the specified port in order to make the communication between container and outside world
EXPOSE 8080
VOLUME: It enable access from your container to a directory in the host machine.
VOLUME: /MYVOLUME
CMD: It provides defaults for an executing container. CMD is default argument passed to the ENTRYPOINT,
Note: Argument sets with CMD can be overridden by RUN
CMD "echo "Hello World"
ENTRYPOINT: Use to execute any executable file during run time. It cannot to override it an immutable command.
ENTRYPOINT: echo
WORKDIR: it’s directive to point the location where the command defined with CMD runs
WORKDIR ~/
ENV: It used to set environment variables this value can be accessed via running scripts.
ENV foo=/bar
USER: It used to set the UID/Username
USER: 588
ADD: It can able to copy the content from remote URL or extracting a file to the container.
ADD http://example.com/foobar /