sub update {
  my ( $url, $dir ) = @_;
  my @possible_suffixes = qw( .gz .bz2 );
  my $basename = extract_basename( $url, @possible_suffixes );
  my $local_file = "$dir/$basename";

##</code><code>##

  return if -e $local_file and not is_newer( $url, $local_file );

##</code><code>##

  my $temp_file = download( $url, TEMP_DIR ) or die "download of $url failed";

##</code><code>##

  if ( -e $local_file ) {
    my $new_name = rename_file( $local_file, suffix( time ) );
    compress( $new_name );
  }

##</code><code>##

  move_file( $temp_file, $local_file );
  maybe_uncompress( $local_file );

##</code><code>##


  return 1;
}