% mix new echo_server
...
% find ./echo_server -type f
./echo_server/mix.exs
./echo_server/config/config.exs
./echo_server/.gitignore
./echo_server/lib/echo_server.ex
./echo_server/test/echo_server_test.exs
./echo_server/test/test_helper.exs
./echo_server/README.md