Dockerfile-build

# Use the Alpine base image as the basis for the container
FROM alpine 

# Set the working directory for Docker to run the commands that follow
WORKDIR /opt

# When the container is run, Docker will concatenate the following list of strings with a space between each string and execute the resulting command string: 
# cat header.txt file-list.txt footer.txt
CMD ["cat", "header.txt", "file-list.txt", "footer.txt"] 

# Copy the project text files into the Docker image working directory
COPY *.txt ./