Beginner's Elixir version of Avdi's anagram for Hello Crystal http://devblog.avdi.org/2015/08/20/hello-crystal/

anagram.exs

defmodule Anagram do

  def table(file, table) do
    case IO.read(file, :line) do
      line when line != :eof ->
        word = String.replace(line, ~r/\n/, "")
        key = to_key(word)

        row = table[key] || []
        row = row ++ [String.downcase(word)]
        table = Dict.put(table, key, row)
        table(file, table)

      _ ->
        File.close(file)
        table
    end
  end

  def to_key word do
    word
    |> String.downcase
    |> String.to_char_list
    |> Enum.sort
    |> List.to_string
  end
end

{:ok, file} = File.open "/usr/share/dict/words"
table = Anagram.table(file, Map.new)

[ word | _ ] = System.argv
word = String.downcase(word)
key = Anagram.to_key word

anagrams = List.delete table[key], word
if Enum.empty?(anagrams) do
  IO.puts "Sorry, no anagrams for '#{word}'"
else
  IO.puts "Anagrams for '#{word}': #{Enum.join(anagrams, ", ")}"
end

Sample benchmark:

elixir_first_steps|master⚡ ⇒ time elixir anagram.exs "avdi"
Anagrams for 'avdi': avid, diva
elixir anagram.exs "avdi"  11.30s user 0.45s system 100% cpu 11.727 total

benchmarks vs. avdi and ruby?