ruby-replace

#!/usr/bin/env ruby

if ARGV.size < 2
  puts "USAGE: ruby-replace FROM TO FILES..."
  puts
  puts "ALTERNATIVE:"
  puts "ls | ruby-replace FROM TO"
  exit
end

from = ARGV[0]
to = ARGV[1]
files = ARGV[2..-1].any? ? ARGV[2..-1] : STDIN.each_line.to_a.map(&:strip)

files.each do |file|
  next if File.directory?(file)
  File.write(file, File.read(file).gsub(from, to))
end