ruby xmlファイルの変更

Windowsプラットフォーム

require 'rexml/document'
include REXML

def modify_xml_file(xml_file_name, id, ipAddress)

        File.open(ARGV[1], 'r') do |file|
						doc = Document.new(file)
						root = doc.root
						if id.instance_of?(Float)
 							id = id.to_s
							id = id[0, id.index('.')]
						end
						root.attributes['NEIPAddress'] = ipAddress
						root.attributes['MeID'] = id
						File.open(xml_file_name, 'w') do |xml_file|
 							doc.write(xml_file)
						end
        end

end