FROM busybox
CMD ["/bin/echo", "glad"]
...
$ docker build -t killme .
Sending build context to Docker daemon 16.38 kB
Sending build context to Docker daemon
Step 0 : FROM busybox
 ---> a9eb17255234
Step 1 : CMD ["/bin/echo", "glad"]
 ---> Running in a4b7bd8b3599
 ---> 9171c8efb1c4
Removing intermediate container a4b7bd8b3599
Successfully built 9171c8efb1c4
...
$ docker run killme
glad
...
$ docker run -i -t --cidfile autodoid.cid killme /bin/echo sad
sad
...
$ docker commit b8e937a0506774a351211ab4cf7a751c7b06e8a33bcfd512f44d0c29651a8be5 killme2
...
$ docker run killme2
sad