See the https://github.com/emccode/snake_charmer page for more details.
Currently it is configured to receive as environment variables access_key, secret_key, proxy_host, and proxy_port. In this example we have also specified the
--net parameter to allow the container to speak with another container running a local S3 instance.
docker run -e 'firstname.lastname@example.org' -e 'secret_key=+zjItiWiOVTrx00AiDRJOOvpFDQ+Hnwsn7aAJzsq' -e proxy_host=127.0.0.1 -e proxy_port=10101 -ti --net container:769 emccode/s3proxycmd ls
The Github page has more details and examples.