    # File lib/phusion_passenger/utils/hosts_file_parser.rb, line 36
            def initialize(filename_or_io = "/etc/hosts")
                    if filename_or_io.respond_to?(:readline)
                            read_and_parse(filename_or_io)
                    else
                            File.open(filename_or_io, "rb") do |f|
                                    read_and_parse(f)
                            end
                    end
            end