#!/usr/bin/perl
use warnings;
use strict;
use feature qw{ say };

my @array= qw( a b c d e f g h i );
my $size = 2;

my $i = 1;
while (@array) {
    open my $out, '>', "$i.txt" or die $!;
    say {$out} $_ for splice @array, 0, $size;
    ++$i;
}
say $i - 1, ' files created.';