list_files path do |file|
                File.open(file) do |source|
                    source.rewind
                    r = Regexp.new(Regexp.union(@@license_identifiers), Regexp::IGNORECASE)

                    extract = source.readlines.slice(block_start, block_size)
                    if extract.grep(r)
                        #puts "Ok"
                    end
        end
        end