Re: singleton for script with shebang

[Bradley Asztalos]

That would work. 

Does --semaphoretimeout 0 mean never give up?

If so then -0 could mean give up immediately.

By the way the note on the sem man page says that sem --timeout is not implemented. 

       --timeout secs (not implemented)
       -t secs (not implemented)
                If the semaphore is not released within secs seconds, take itanyway.

And indeed testing of (parallel --version \n GNU parallel 20141022) indicate that it does not work. Anyway great product, thanks Ole.

Bradley

On Fri, Jan 2, 2015 at 7:35 AM, Ole Tange <ole@tange.dk> wrote:

On Fri, Jan 2, 2015 at 10:51 AM, Bradley Asztalos
<brad@customweather.com> wrote:

> Taking this one step further, I know of course there are other ways to do
> this, but what about a way to have sem die if it cannot immediately acquire
> execute? Something like --die_young so that it could be used not only to
> serialize but to disallow a run if there is already a process running with
> the same lock_id.

So that is almost the opposite of --semaphoretimeout

Maybe it should be able to take a negative value: If you cannot get
the semaphore within 2 seconds, give up.

sem --semaphoretimeout -2 do_stuff


/Ole