Actually hardly any of the OP's lines were more than one line. However, processing the OP code through Perl tidy and with a little hand tidying (including adding strictures and some blank lines) the code is still only 62 lines long:

use strict;
use warnings;

print "\nUse: SIZE START_X START_Y [0,1]" and exit if @ARGV < 4;

my ($N, $X0, $Y0, $VERBOSE) = @ARGV;
my $MOVES = 0;
my @moves = ([-2, -1], [-1, -2], [-2, 1], [-1, 2], [2, -1], [1, -2], [
+2, 1], [1, 2]);
my @board;

my $last_move = [$X0, $Y0] and inform_board ();

$last_move = inform_board ($last_move) while $MOVES < $N * $N;


sub init {
    return ($_[0] > $N / 2) ? init ($N - 1 - $_[0], $_[1])
        : (
        $_[1] > $N / 2 ? init ($_[0], $N - 1 - $_[1])
        : (
            $_[0] >= 2
                && $_[1] >= 2 ? 8
            : (   ($_[0] >= 2 && $_[1] == 1 || $_[1] >= 2 && $_[0] == 
+1) ? 6
                : ($_[0] + $_[1] > 1 ? 4 : ($_[0] + $_[1] == 1 ? 3 : 2
+)))
            )
            );
}

sub inRange {
    my ($pos, $D) = @_;
    my ($x, $y) = ($pos->[0] + $D->[0], $pos->[1] + $D->[1]);
    return ($x >= 0 && $x < $N && $y >= 0 && $y < $N && $board[$x][$y]
+ >= 0)
        ? [$x, $y]
        : 0;
}

sub inform_board {
    my ($moved_to) = @_;

    if ($moved_to) {
        $MOVES++;
        print "\n$MOVES.$moved_to->[0], $moved_to->[1]" if $VERBOSE;
        my ($MIN, $next_to_move) = (10, []);

        foreach (@moves) {
            if (my $finalPos = inRange ($moved_to, $_)) {
                my $value_ref = \$board[$finalPos->[0]][$finalPos->[1]
+];
                ($MIN, $next_to_move, $board[$moved_to->[0]][$moved_to
+->[1]]) =
                    ($$value_ref, $finalPos, 0)
                    if (--$$value_ref >= 0 && $$value_ref < $MIN);
            }
        }

        return $next_to_move;
    } else {
        push @board, [(0) x $N] for (1 .. $N);

        for my $i (0 .. $N - 1) {
            $board[$i][$_] = init ($i, $_) for 0 .. $N - 1;
        }
    }
}
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