Thanks. I appreciate your reply. In my particular application, the three situations that you mention: 1) match multiple instances 2) both exit 3) neither exit if name has changed, are acceptable or even desirable. I forgot to mention that my scripts will be scheduled by cron to run every minute, but sometimes they will take more than one minute to complete. If one newly starting instance exits unnecessarily, it is ok since it will run again the next minute.

What would not be acceptable though, would be if they both have the same name but, for some reason neither of them exit. I just figured that it might be less messy than having to deal with lock files, which if I understand the previous threads on the subject, can also have a race condition.