iex -S mix phx.server: What? How?

iex -S mix phx.server : it starts up my Phoenix dev server under Elixir's interactive shell program, IEx , so I can call functions from my app and whatnot . One day, it started to bug me unreasonably much that I didn't really understand how this command causes that to happen. Perhaps culpable: a touch of delirium, downstream of the flu. There were a lot of reasons for my mystification (i.e. a lot…