$starttime = time;
printf ("start - %d\n",$starttime);
$pref = "";
for ($j = 0; $j < 10; $j++)
{
	unlink "-$j";
}

sortfile("numbers.dat", $pref, 7);

for ($i = 6; $i >= 0; $i--)
{
	for ($j = 0; $j < 10; $j++)
	{
		unlink "$pref-A-$j";
	}

	for ($j = 0; $j < 10; $j++)
	{
		sortfile("$pref-$j", "$pref-A", $i);
	}
	$pref .= "-A";
}

printf ("end sort - %d (%d)\n",time, time - $starttime);
open (FILE, ">sorted.dat") || die;
for ($i = 0; $i < 10; $i++)
{
	open(IN, "$pref-$i") || die;
	while(<IN>)
	{
		print FILE $_;
	}
	close(IN);
}
close(FILE);

printf ("end - %d (%d)\n",time, time - $starttime);

sub sortfile
{
	my ($source, $pref, $offset) = @_;
	my $i, @fh;
	printf("$offset $pref $source - %d\n", time - $starttime);
	
	open(FILE, $source) || die;
	for ($i = 0; $i < 10; $i++)
	{
		open($fh[$i], ">>$pref-$i") || die;
	}
	
	while(<FILE>)
	{
		$f = $fh[substr($_, $offset, 1)];
		print $f $_;
	}
	
	close(FILE);
	
	for ($i = 0; $i < 10; $i++)
	{
		close($fh[$i]);
	}
}