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Re: Feature request: Can bash provide some mechanism for locking/unlock
From: |
Clark J. Wang |
Subject: |
Re: Feature request: Can bash provide some mechanism for locking/unlocking? |
Date: |
Fri, 16 Apr 2010 12:05:47 +0800 |
On Fri, Apr 16, 2010 at 10:52 AM, Bob Proulx <bob@proulx.com> wrote:
> Clark J. Wang wrote:
> > Bob Proulx wrote:
> > > There is also 'lockfile' distributed with 'procmail'.
> >
> > By using `lockfile' we must make sure that our script will not crash and
> > the file is unlocked when the script exits.
>
> True. That is true of any of the file based locking methods. And
> advantage to the flock/lockf based methods such as flock(1). But I
> almost always have cleanup traps for other reasons and incorporate the
> cleanup there to ensure that the lockfile is removed by the creating
> process when it exits.
>
Yes, cleanup traps are fine.
>
> As far as needing to make sure that your script doesn't crash, well,
> don't you need to do that anyway? :-)
>
Agree.
>
> > Although it provides timeout mechanism it's still not so convinient.
>
> Beware of the timeout. That isn't safe and may violate your mutual
> exclusion section. Actually it almost certainly will violate it.
>
> Bob
>
>
>
Re: Feature request: Can bash provide some mechanism for locking/unlocking?, Jan Schampera, 2010/04/15