This is a very simple shellapp for educational purposes. It demostrates how you can use STDIN and STDOUT in docker.
-$ git clone git@github.com:gregkoul/Dockerized-shellapp-stdin.git
-$ cd Dockerized-shellapp-stdin
-$ docker build . -t gregkoul/shellapp-stdin:1.1
-$ docker run gregkoul/shellapp-stdin:1.1
-$ docker run -it gregkoul/shellapp-stdin:1.1