If LIMIT is omitted, split removes trailing empty fields. If LIMIT is negative, split keeps all fields.

split-test.pl

#!/usr/bin/perl
use strict;
use warnings;
use 5.10.0;

my $str = 'aaa::bbb:::fff::::';

# no limit
my @array1 = split /:/, $str;
say join ',', @array1; # => aaa,,bbb,,,fff

# smaller
my @array2 = split /:/, $str, 8;
say join ',', @array2; # => aaa,,bbb,,,fff,,::

# bigger
my @array3 = split /:/, $str, 100;
say join ',', @array3; # => aaa,,bbb,,,fff,,,,

# negative
my @array4 = split /:/, $str, -1;
say join ',', @array4; # => aaa,,bbb,,,fff,,,,