That solution isn't terribly efficient, however, since the entire array (which is specified as being huge) has to be rewritten for every splice. You're splicing from the start, not the end, and might do better splicing in reverse and then reversing. Alternately, you could make a copy of the array contents instead of splicing:

use strict;
use warnings;

my (@arr, @arr2, $i);

$arr[$_] = $_ for 0..357;

for ($i = 0; $i <= $#arr; $i += 50) {
    push @arr2, [@arr[$i..($i+49)]];
}
$#{$arr2[$#arr2]} = $#arr % 50;

print join(' ', @$_), "\n" for @arr2;
[download]

Yes, this has a memory cost twice that of the original array, but you're going to need that even with the spliced solution, since I don't believe the extra space is returned to the script as the array is reduced in size?