[Perl] Desofuscador de Batchs

#!/usr/bin/perl

my %vars;
my @newcode="";

open(FILE, "<$ARGV[0]");
@codigo=<FILE>;
close(FILE);

foreach $linea(@codigo)
{
	if($linea=~/set (.+)="(.+)"/)
	{
		$vars{$1}=$2;
	}
	$linea=~s/%(\w+):~(\d+),(\d+)%/substr($vars{$1},$2-1,$3)/eg;
	push(@newcode,$linea);
}
print @newcode;