use File::Find;
use File::stat;

our @current_bucket;
our $current_size = 0;
our $BUCKET_SIZE = 4000000000;
sub add_to_bucket {
  my $size = stat($_)->size();
  if ($size + $current_size > $BUCKET_SIZE) {
     # reset bucket
     process_bucket(\@current_bucket);
     @current_bucket = ();
     $current_size = 0;
  }
  $current_size += $size;
  push @current_bucket, $File::Find::name;
}

sub process_bucket {
   my $bucket = shift;
   # here do things like compress the list to contain
   #  parent directories, etc, if you really need to do this
   # then print out the list.   
} 

find(\&add_to_bucket, "/data");