finding anagrams

gistfile1.rb

require 'set'

str = String.new(ARGV[0])
if str.nil? || str.length < 2 then
   puts "usage: anagram <string>"
   exit
end

anagram_set = SortedSet.new
(0..str.length-1).each do
  (0..str.length-1).each do |i|
    str_builder = str[i..i]
    anagram_set.add(str_builder)
    (0..str.length-1).each do |j|
      if i != j then
        str_builder += str[j..j]
        if !anagram_set.member?(str_builder) then
          anagram_set.add(str_builder)
        end
      end
    end
  end
  #shift
  str = str[str.length-1..str.length-1] + str.chop
end

puts anagram_set.to_a