my @c_speed = (5, 8, 12, 8);
my $sfh;
  open($sfh, '>', $save_fn) or
        die "Unable to open file $save_fn : $!";
  print $sfh "@c_speed\n";

...

The file contains a line that looks like "5 8 12 8\n"
...

my $lfh;
  open($lfh, '<', $load_fn) or
        die "Unable to open file $load_fn : $!";
$rstring  = <$lfh>;  # Char speeds
  ($c_speed[0], $c_speed[1], $c_speed[2], $c_speed[3]) = sscanf("%d %d %d %d", $rstring);