convert files/directories to ensure utf8 marker.

utf8.rb

#! /usr/bin/env ruby
# encoding: utf-8

#
# converts files to include a utf8 marker
#
# usage: utf8 files_or_directories

##
#
  argv = ARGV.map{|arg| "#{ arg }"}
  stdin = argv.delete('-')
  argv.push(STDIN.readlines) if stdin

  argv.flatten!
  argv.compact!
  argv.uniq!

  files, directories = argv.partition{|arg| test(?f, arg)}

  directories.each do |directory|
    glob = File.join(File.expand_path(directory), '**/**')

    Dir.glob(glob) do |entry|
      files.push(File.expand_path(entry)) if test(?f, entry)
    end
  end

  argv.flatten!
  argv.compact!
  argv.uniq!

##
#
  utf_8 = "# encoding: utf-8"

  files.each do |file|
    head = []
    tail = []

    shebang = nil
    had_encoding_line = false

    open(file, 'r+') do |fd|
      in_tail = false

      fd.each do |line|
        if in_tail
          tail.push(line)
          next
        end

        head.push(line)

        is_blank = line.strip.empty?
        is_shebang = line =~ /^\s*#\s*!/
        is_encoding = line =~ /^\s*#.*(encoding|coding)/

        if is_blank
          next
        end

        if is_shebang
          shebang ||= line
          next
        end

        if is_encoding
          had_encoding_line ||= line
          next
        end

        in_tail = true
      end
    end

    unless had_encoding_line
      open(file, 'w') do |fd|
        fd.puts(shebang) if shebang
        fd.puts(utf_8)
        fd.puts
        fd.write(tail.join)
      end

      puts(file)
    end
  end