What is IEx?

The good news: Elixir includes a tool called a Read-Evaluate-Print-Loop (REPL), which is essentially an Elixir shell. You can think of this as being similar to an irb in Ruby or the node shell in Node.js. It is a very detailed and helpful tool that we'll be referring to quite a bit in our journey of building this full web app! To open REPL up (assuming you have Elixir installed), run the following command:

$> iex

You should see something similar to the following snippet appear on your screen:

$> iex
Erlang/OTP 20 [erts-9.0] [source] [64-bit] [smp:4:4] [ds:4:4:10] [async-threads:10] [hipe] [kernel-poll:false] [dtrace]
Interactive Elixir (1.5.0) - press Ctrl+C to exit (type h() ENTER for help)
iex(1)>

Now we can start messing around with some sample Elixir code! Let's start off with a couple of base scenarios.