Global find and replace with optional confirm

gfr.rb

#! /usr/bin/ruby
require 'rubygems'
require "highline/system_extensions"
include HighLine::SystemExtensions

orig, new, args = ARGV
args = Array(args)

file_names = Dir["**/*.*"]

file_names.each do |file_name|
  text = File.read(file_name)
  if text.index(orig)
    p file_name
    regexp = /(.*)(#{orig})(.*)/

    new_text = text.gsub(regexp) do |line|
      number = $`.split("\n").count + 1
      puts "#{number}: #{line}"

      replacement = if args.include?('-c')
        print "Replace '#{orig}' with '#{new}'? (y/n): "
        input = get_character.chr
        puts
        input == 'y' ? new : orig
      else
        new
      end

      line.gsub(orig, replacement)
    end

    File.open(file_name, "w") do |file|
      file.puts new_text
    end
  end
end

gfr original replacement -c # comfirms each replacement
gfr original replacement # replaces without confirm