Unfortunately this behaviour of stripping trailing null fields is inherent in split's operation (update: unless you take advantage of split's 3rd argument. ahem). An alternate solution would be to apply a capturing regex e.g

use Data::Dumper;

my $txt = 'a,b,c,d,,,,,,';
my @fld = $txt =~ /([^,]*)(?:,|$)/g;

print Dumper \@fld;

__output__

$VAR1 = [
          'a',
          'b',
          'c',
          'd',
          '',
          '',
          '',
          '',
          '',
          ''
        ];
[download]

So that regex captures everything between commas, even null fields. See. perle and perlop for more info.