Enable private browsing mode, open a new page in Safari for the given URL.

safari.rb

#!/usr/bin/env ruby

($stderr.puts(DATA.read.gsub("$0", File.basename($0))); exit 1) if ARGV.length != 1

require 'appscript'

safari_app     = Appscript.app("Safari")
safari_process = Appscript.app('System Events').processes['Safari']

safari_app.activate

private_browsing_menu_item = safari_process
                             .menu_bars.first
                             .menu_bar_items['Safari']
                             .menus['Safari']
                             .menu_items['Private Browsing']

private_browsing_enabled = !private_browsing_menu_item.attributes['AXMenuItemMarkChar'].value.get.nil?

private_browsing_menu_item.click unless private_browsing_enabled

safari_app.open_location(ARGV[0])


__END__
Enable private browsing mode, open a new page in Safari for the given URL.

Usage:
  $0 <URL>

Example:
  $0 http://heroku.com