[翻訳]Elixirでコマンドラインアプリケーションを書く ref: http://qiita.com/hideshi@github/items/615e4f859a2486e7ab58

file1.txt

defmodule EightBall.CLI do
  def main(args) do
  end
end

file10.txt

"Question must be a string, ending with a question mark."

file11.txt

mix escript.build

file12.txt

➜  eight_ball git:(master) ✗ mix escript.build
Compiled lib/eight_ball.ex
Generated eight_ball app
Generated escript eight_ball with MIX_ENV=dev

file13.txt

➜  eight_ball git:(master) ✗ ./eight_ball --question "Is Elixir awesome?"
Outlook good

file14.txt

➜  eight_ball git:(master) ✗ ./eight_ball --question "Is Elixir awesome"
Question must be a string, ending with a question mark.

file2.txt

eight_ball --question "Is Elixir great?"

file3.txt

eight_ball -q "Is Elixir great?"

file4.txt

defmodule EightBall.CLI do
  def main(argv) do
    {options, _, _} = OptionParser.parse(argv, 
      switches: [question: :string],
    )

    IO.inspect options
  end
end

file5.txt

mix escript.build

file6.txt

➜  eight_ball git:(master) ✗ mix escript.build
Compiled lib/eight_ball/cli.ex
Generated eight_ball app
Generated escript eight_ball with MIX_ENV=dev

file7.txt

./eight_ball --question "Is Elixir great?"

file8.txt

➜  eight_ball git:(master) ✗ ./eight_ball -q "Is Elixir great?"
[question: "Is Elixir great?"]

file9.txt

defmodule EightBall.CLI do
  def main(opts) do
    {options, _, _} = OptionParser.parse(opts, 
      switches: [question: :string],
      aliases: [q: :question] # makes '-q' an alias of '--question'
    )

    try do
      IO.puts EightBall.ask(options[:question]) 
    rescue 
      e in RuntimeError -> e
        IO.puts e.message
    end
  end
end

mix.exs

defmodule EightBall.Mixfile do
  use Mix.Project

  def project do
    [app: :eight_ball,
     version: "0.0.1",
     elixir: "~> 1.0",
     build_embedded: Mix.env == :prod,
     start_permanent: Mix.env == :prod,
     escript: [main_module: EightBall.CLI], # <- this line
     deps: deps,
     package: package ]
  end
  # ...
end