find コマンドみたいなの

find.rb

# -*- coding: utf-8 -*-
# usage: ruby find.rb ~ --name .* --depth 1
# need to OptParser
require "optparser"

$filename = nil
$rootdir = File.expand_path '.'
$recursive = true
OptParser.add_option('--name') { |filename|
  $filename = filename
}
OptParser.add_option('--depth') { |depth|
  $recursive = depth.to_i
}
OptParser.main = proc { |rootdir|
  $rootdir = File.expand_path rootdir
}
OptParser.parse_options

unless $filename
  puts "plz to put --name"
  exit
end

unless File.exist? $rootdir
  puts "#{$rootdir} is not exist."
end

unless File.directory? $rootdir
  puts "#{$rootdir} is not directory."
end

def find rootdir, wantfilename=/.*/, recursive=true, &callback
  res = []
  Dir.entries(rootdir)[2..-1].each do |entry|
    res << entry if entry =~ wantfilename
    abspath = "#{rootdir}/#{entry}"
    case recursive
    when Numeric
      if (File.directory? abspath) && (recursive > 0)
        callback.call abspath if callback
        res += find abspath, wantfilename, recursive-1, &callback
      end
    else
      if (File.directory? abspath) && recursive
        callback.call abspath if callback
        res += find abspath, wantfilename, recursive, &callback
      end
    end
  end
  res
end

find($rootdir, Regexp.new($filename), $recursive) { |filename| puts filename }