Docker can build images automatically by reading the instructions
from a Dockerfile. A Dockerfile is a text document that contains
all the commands a user could call on the .command line to assemble
an image. Using docker build users can create an automated build
that .executes several command-line instructions in succession.
This page describes the commands you can use in a Dockerfile. When
you are done reading this page, refer to the Dockerfile Best
Practices for a tip-oriented guide.