I was challenged (in the CB) to come up with a file based locking mechanism that would solve atcroft's throttling problem. Additionally, I was asked that it

The following is my best stab. It looks a little too short to be correct ... can anyone see problems (and ideally, solutions)? You may want to cf. LockFile::Simple.

$LOCK = $0;
$MAX_RUNNING = 10;

sub lock_count
{
   return scalar split /\s+/, `fuser $LOCK 2>/dev/null`;
}

die ("Too many running processes")  if (&lock_count >= $MAX_RUNNING);
open(LOCK) or die("Failed to acquire lock");
die ("Too many running processes")  if (&lock_count > $MAX_RUNNING);

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In reply to File Based Throttling by idsfa

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