This is a simple ( though not very Ruby idiomatic ) example of how to determine what anagrams exist in a dictionary. The algorithm used is Knuth's anagram algorithm. Idiomatic Ruby has been replaced with an attempt to make the algorithm as readable as possible. Algorithm is O(n), with an additional pass to display / count the number of anagrams.…

knuth_anagrams.rb

def load_words
  formatted_words = []
  File.readlines(ARGV[0]).each{|line| formatted_words << line.chomp.downcase}
  formatted_words
end

def sort_word_alphabetically(unsorted_word)
  unsorted_word.chars.sort.join
end

def sorted_word_hashed?(hash, sorted_word)
  return false if hash[sorted_word] == nil
  true
end

def add_sorted_word_to_hash(word_hash, sorted_word, word)
  anagram_arr = []
  anagram_arr << word
  word_hash[sorted_word] = anagram_arr
end

def add_word_to_anagram_arr(word_hash, sorted_word, word)
  anagram_arr = word_hash[sorted_word]
  anagram_arr << word
  word_hash[sorted_word] = anagram_arr
end

def count_annagrams(word_hash, display_anagrams=false)
  total = 0
  word_hash.each do |key, arr|
    if arr.length > 1 then
      total += 1
      puts arr.join(" ") if display_anagrams
    end
  end
  total
end

words = load_words
word_hash = Hash.new
words.each do |word|
  sorted_word = sort_word_alphabetically word
  if sorted_word_hashed?(word_hash, sorted_word) then
    add_word_to_anagram_arr(word_hash, sorted_word, word)
  else
    add_sorted_word_to_hash(word_hash, sorted_word, word)
  end
end

puts "Total anagrams ---> #{count_annagrams(word_hash, true)}"