Global find and replace with optional confirm (with colored diff)

gfr.rb

#! /usr/bin/env ruby

# Save this file to somewhere in your PATH, like ~/bin/gfr, and chmod it with: chmod u+x gfr

require 'rubygems'
require "highline/system_extensions"
require 'colorize'
require 'optparse'
require 'ostruct'
include HighLine::SystemExtensions

def ignore_patterns
  @ignore_patterns ||= begin
    ignore_file = "#{ENV['HOME']}/.gfr_ignore"
    File.exists?(ignore_file) ? File.read(ignore_file).split(/\s+/) : []
  end
end

def ignorable?(file_name)
  ignore_patterns.each do |pattern|
    return true if File.fnmatch(pattern, file_name)
  end
  false
end

def usage_and_quit
  $stderr.puts banner
  exit 2
end

def banner
  "Usage: gfr [options] SEARCH REPLACE"
end

def parse_opts
  options = { :confirm => false }
  OptionParser.new do |opts|
    opts.banner = banner

    opts.on("-c", "--confirm", "Confirm each replacement") do |v|
      options[:confirm] = true
    end
  end.parse!
  [ARGV[0], ARGV[1], options]
end

def run
  options = parse_opts
  orig, new, opts = options
  usage_and_quit if !(orig && new)

  #file_names = Dir["**/*.*"]
  file_names = `find . -type f`.split(/[\r\n]+/).reject{ |f| f == '.' || f == '..' }
  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}".red
        puts "+#{number}: #{line}".gsub(orig, new).green

        replacement = if opts[:confirm]
          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
end

run

Enhancements:

• Allows putting the -c argument anywhere in the command arguments
• Allows specifying file patterns to ignore, using an ignore file at ~/.gfr_ignore
• Search files in the current directory too (but calls out to the find command to do this)