use ForkList;

our $URLS;

for $list(@LISTS) {
    $URLS = get_lines($list);
    run( \&callback, scalar(@$URLS), { kids => $KIDS, verbose => $VERBOSE } );
} 

sub callback {
    my ( $child, $i ) = @_;
    my $url = $URLS->[$i];
    my( $code ) = cache_url( $url, $FORCE, $TIMEOUT ); 
    append_file( "$LIST.$code", "$url\n", $child, $i, $VERBOSE );
  return 0;
}