use MCE::Loop chunk_size => 1; my @input_data = (0 .. 100 - 1); mce_loop { my ($mce, $chunk_ref, $chunk_id) = @_; open my $output, '>', "/path/to/my/files/$chunk_id.txt"; foreach (1..10) { print $output "\t",fibonacci($_)}; print $output "\n"; close $output; } @input_data; sub fibonacci { my $n = shift; return undef if $n < 0; my $f; if ($n == 0) { $f = 0; } elsif ($n == 1) { $f = 1; } else { $f = fibonacci($n-1) + fibonacci($n-2); } return $f; }