This image was created by commiting a container running the ubuntu:14.04 image. The many confirmations needed during the install process made it impractical to build from a Dockerfile.
The only version til now is sqlanywhere 17.0 and there's no current entrypoint for the image, nor a cmd. Therefore, the cmd command from ubuntu image, /bin/bash is still up on this one.
This image by itself can be used to start a server from command line (in or outside the container) or as a base to build a proper Dockerfile with a volume for the data folder and probably a bash script as entrypoint to initialize and run the server (recommended).