List out all INSTRUCTION statement of dockerfile and give one line explanation.

FROM – to specify the parent image. Eg ubuntu from which you create an image
MAINTAINER – to set the author/creater of the image
RUN – to run a command like shell script in linux or execute a program
ARG – should be used along with FROM to speficy any arguments lie version
EXPOSE – To inform the docker that the container listern on the given port
COPY – to copy files or dir to the container destination path
ADD – to copy files or dir to the container destination path. It will extract the files if it is a zip
USER – to set the runtime user
CMD – to set the default executable
ENTRYPOINT – to specify the executables.
ENV – to set enviornment variabl
VOLUME – to create a mount
WORKDIR – to set teh current working directory