Date: Fri, 21 Jun 2002 11:45:00 -0400 From: Garance A Drosihn <drosih@rpi.edu> To: Mikhail Teterin <mi+mx@aldan.algebra.com>, Juli Mallett <jmallett@FreeBSD.ORG> Cc: arch@FreeBSD.ORG Subject: Re: feature request for xargs Message-ID: <p0511178cb938f5a581d7@[128.113.24.47]> In-Reply-To: <200206211033.03948.mi%2Bmx@aldan.algebra.com> References: <200206200706.g5K76M514469@freefall.freebsd.org> <200206202012.17801.mi%2Bmx@aldan.algebra.com> <20020620175700.A96462@FreeBSD.ORG> <200206211033.03948.mi%2Bmx@aldan.algebra.com>
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At 10:33 AM -0400 6/21/02, Mikhail Teterin wrote: >On Thursday 20 June 2002 08:57 pm, Juli Mallett wrote: >= I'd been hesitant on this, until we were clear on how it could >= and would be used, but an arch@ review is probably enough :) I think it could be a useful option. >Here is the usage, for which I currently use make(1). [...]. >This works good, but may be done simpler with something like > > echo *.JPG | xargs -n1 -j2 <script> Note that it would be: echo *.JPG | xargs -n 1 -j 2 <script> (with blanks after -n and -j :-) > >All operations, involving many light tasks can benefit, i.e. > > find /some/dir \! -type d -print0 | xargs -0 -j0 rm -f It's not clear to me that this specific case would benefit. If you have a large number of files, then this will spawn off a large number of processes, only to see those processes fight with each other over updating entries in the directories (as well as fighting with the 'find' itself, as it searches through those very same directories). You might want to do the above to clean out /usr/obj/usr/src, for instance, but I suspect that would be a bad idea. In thinking about that example, I wonder if we should not allow '-j 0' to spawn infinite processes. Maybe allow a -j value from 1 to 64 (or some other arbitrary number), just to reduce the chances of a one-line "fork bomb". -- Garance Alistair Drosehn = gad@gilead.netel.rpi.edu Senior Systems Programmer or gad@freebsd.org Rensselaer Polytechnic Institute or drosih@rpi.edu To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
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