ruby遍歷文件夾計算md5sum

#!/usr/bin/ruby -w
#
require 'digest/md5'

if ARGV.empty?
        puts "usgae: #$0 path"
        exit 0
end
dir_name=ARGV.shift

def dir_md5sum(path)
        md5s=Array.new
        if File.directory?(path)
                Dir.new(path).each do |file|
                        next if file =~ /^\.+$/
                        file="#{path}/#{file}"
                        if File.directory?(file)
                                dir_md5sum(file)
                        elsif File.file?(file)
                                md5="#{Digest::MD5.hexdigest(File.read(file))} #{file}"
                                md5s.push(md5)
                        end
                end
        elsif File.file?(path)
                md5="#{Digest::MD5.hexdigest(File.read(path))} #{path}"
                md5s.push(md5)
        else
                puts "Ivalid File type"
                exit 2
        end
        md5s.each do |item|
                puts item

        end
end

dir_md5sum(dir_name)