[ale] Only one process

[scott]

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On Jun 4, 2010, at 8:49 PM, JK wrote:

> Doesn't anybody worry about race conditions any more?  How do you
> defend against multiple copies of this script running simultaneously?
> Of course, cron *shouldn't* ever do that...
> 
> flock(1) seems relevant:
> 
> http://linux.die.net/man/1/flock
> 
> -- JK

when I write scripts that I dont want to run in parallel.  I check for a /var/run/*.pid file related to the script and if the PID in it isnt mine, then I abort out. if the file isnt there, I create it with my PID.  And when the script exits it removes the file.
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