Implementation of CodeKata#6 http://codekata.pragprog.com/2007/01/kata_six_anagra.html

anagrams.rb

class Anagrams
  def self.process(word_list)
    word_list.group_by {|word| word.strip.downcase.chars.sort.join }.
      values.map {|v| v.map(&:strip).join(" ")}
  end 
end

anagrams_spec.rb

require 'minitest/spec'
require 'minitest/autorun'
require 'minitest/pride'
require 'anagrams'

describe Anagrams do
  it "finds a simple anagram" do
    words = %w[ink kin]

    output = Anagrams.process(words)

    output.count.must_equal 1
    output.must_equal ["ink kin"]
  end 

  it "groups anagrams on separate lines" do
    words = %w[arrest foo ink kin rarest]

    output = Anagrams.process(words)

    output.count.must_equal 3
    output.must_equal ["arrest rarest", "foo","ink kin"]
  end 
end

run_anagrams.rb

#!/usr/bin/env ruby
require_relative 'anagrams.rb'
USAGE = "run_anagrams.rb <wordlist>

Will output a list of all words in the wordlist, with anagrams on the same line.

I used http://spacebar.org/ifcd/wordlist.txt as a sample wordlist.

Example: 
Given this input file:

 foo
 ink
 kin

The output will be:

 $ ./anagrams.rb input_file.txt
 foo
 ink kin
"

unless ARGV.length > 0 
  $stderr.puts USAGE
  exit 1
end

puts Anagrams.process(IO.readlines(ARGV[0]))