Convert XML to JSON using Ruby and ActiveSupport

How to convert XML to JSON using Ruby and ActiveSupport:

#! /usr/bin/env ruby

    require 'rubygems'
    require 'active_support/core_ext'
    require 'json'
    
    xml = File.open(ARGV.first).read
    json = Hash.from_xml(xml).to_json
    
    File.open(ARGV.last, 'w+').write json