>610

use Fcntl qw/:flock/;

open my $fh, '+<', './count.dat' or die $!;
eval { flock $fh, LOCK_EX };
$count = <$fh>;
seek $fh, 0, 0;
print $fh $item == 1 ? $count + 1 : $count -1;
truncate $fh or die $!;
close $fh;