Simple and plain:

• It exposes the ShellInABox daemon on port 4200, as HTTPS with a self-signed SSL certificate.
• It provides a login shell to a user inside the container.
• The user is named user and the password can be passed via the environment variable $PASSWORD.
• An openssh client is available in the container to access the host system.

If you need more commands, just use this image as base and apt install whatever you need.

If you need a signed HTTPS certificate, put an instance of nginx-proxy with its Let's Encrypt companion in front.