A script for searching a dictionary file for words that are relatable via a simple text substitution

change-x-for-y.rb

# Inspired by a church billboard that read:
#   "When I becomes we, illness becomes welness"
#
# usage:
# > ruby change-x-for-y.rb i we
# illness wellness
# inch wench
# it wet
# ...

a = ARGV.shift or "you must specify two words that are replaceable"
b = ARGV.shift or "you must specify TWO words that are replaceable"

a = a.downcase
b = b.downcase

words = File.readlines("/usr/share/dict/words").map { |w| w.strip.downcase }
dict = words.inject({}) { |h,k| h[k] = k.length; h }

words.each do |word|
  next if word == a
  word2 = word.gsub(/#{a}/, b)
  if word2 != word && dict[word2]
    puts "#{word} -> #{word2}"
  end
end