replace

#!/usr/bin/env perl

use Data::Dumper;
use FindBin;
use lib "$FindBin::Bin/lib";
use Minecraft;
use Getopt::Long;

my $worldname;
my $from;
my $to;
my $help;

BEGIN { 
	sub help 
	{
		print "$0 <world-name> <from-block-id> <to-block-id>\n";
	}

	if( !GetOptions (
              	"help"  => \$help,
	)) {
		print STDERR ("Error in command line arguments\n");
		help();
		exit( 1 );
	}

	($worldname,$from,$to) = @ARGV;
}

use strict;
use warnings;

if( $help )
{
	help();
	exit( 0 );
}

my( $from_block, $from_st ) = split( /\./, $from );
my( $to_block, $to_st ) = split( /\./, $to );

$to = sprintf( "%d.%02d", $to_block, $to_st );


if( !defined $worldname )
{
	die "No worldname given";
}

if(! -e "$FindBin::Bin/saves/$worldname" )
{
	die "Can't find world $worldname";
}

my $mc = new Minecraft( "$FindBin::Bin/saves" );
my $world = $mc->world( $worldname );
my @regions = $world->regions;
for( my $reg_i=0;$reg_i<scalar @regions; $reg_i++ ) {
	my $r_pos = $regions[$reg_i];
	my $region= $world->region( $r_pos->[0], $r_pos->[1] );
	print "Region ".($reg_i+1)." of ".(scalar @regions)." [".$r_pos->[0].",".$r_pos->[1]."] .. ";
	my $changed = 0;
	
	for( my $c_z=0; $c_z<32; ++$c_z )
	{
		X: for( my $c_x=0; $c_x<32; ++$c_x )
		{
			next X if( !defined $region->{$c_z}->{$c_x} );
			my $chunk = $region->{$c_z}->{$c_x}->{chunk};
			# print "($c_x)($c_z)\n";
			my $sections = $chunk->{Level}->{Sections}->{_value};

			for( my $section_y=0; $section_y<scalar @$sections; ++$section_y ) 
			{
				for( my $s_y=0;$s_y<16;$s_y++) {
					for( my $s_x=0;$s_x<16;$s_x++) {
						for( my	 $s_z=0;$s_z<16;$s_z++) {
							my $bx = $c_x*16 + $s_x;
							my $by = $section_y*16 + $s_y;
							my $bz = $c_z*16 + $s_z;
							my $block = $region->get_block( $bx,$by,$bz );
							my $subtype = 0;
							if( $block == $from_block ) {
								$subtype = $region->get_subtype( $bx,$by,$bz );
								if( $subtype == $from_st ) {
									$region->set_block( $bx,$by,$bz, $to );
									$changed++;
								}
							}
						}
					}
				}

			}
		}
	}

	print "$changed blocks modified\n";
	$world->save;
}
print "DONE\n";

exit;