Date: Sun, 22 Apr 2001 19:30:45 +0200 From: "Karsten W. Rohrbach" <karsten@rohrbach.de> To: Brian Dean <bsd@bsdhome.com> Cc: Sheldon Hearn <sheldonh@uunet.co.za>, freebsd-current@FreeBSD.ORG Subject: Re: cp -d dir patch for review (or 'xargs'?) Message-ID: <20010422193044.B92712@mail.webmonster.de> In-Reply-To: <20010421162436.A56976@vger.bsdhome.com>; from bsd@bsdhome.com on Sat, Apr 21, 2001 at 04:24:36PM -0400 References: <200104211527.RAA06452@lurza.secnetix.de> <67741.987867271@axl.fw.uunet.co.za> <20010421162436.A56976@vger.bsdhome.com>
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rohrbach@WM:datasink[~]68% tar cf /dev/null src/
rohrbach@WM:datasink[~]69% find src|wc -l
2552
rohrbach@WM:datasink[~]70% du -sk src
32258 src
rohrbach@WM:datasink[~]71% mkdir src2
rohrbach@WM:datasink[~]72% time find src -exec cp {} src2 \;
find src -exec cp {} src2 ; 0.31s user 7.55s system 39% cpu 19.858 total).
rohrbach@WM:datasink[~]73% rm -rf src2
rohrbach@WM:datasink[~]74% mkdir src2
rohrbach@WM:datasink[~]75% time find src | cpio -dup src2
61025 blocks
find src 0.02s user 0.03s system 0% cpu 21.739 total
cpio -dup src2 0.26s user 4.84s system 20% cpu 24.862 total
68: warm up the filecache
69: there are 2552 files
70: they are 32.2MB total
71: ready the target dir
72: find -exec approach, all files to one dir
73: clear target area
74: ready it again
75: let find traverse the dir, cpio transfer the files
the cpio approach keeps the hierarchy which might not be what you want
but it looks more efficient, becouse it does not fork off cp for ecery
file.
/k
Brian Dean(bsd@bsdhome.com)@2001.04.21 16:24:36 +0000:
> On Sat, Apr 21, 2001 at 05:34:31PM +0200, Sheldon Hearn wrote:
>
> > So we have two problems:
> >
> > 1) Calling cp(1) repetitively is inefficient.
> >
> > 2) The argument list is too big for cp(1).
> >
> > Extending cp(1) will not solve (2). Extending xargs(1) will solve both.
> > So why is an extension to cp(1) being proposed?
>
> But extending cp does solve the problem. The proposal was to make
>
> % cp -d target src1 src2 ... srcN
>
> Be equivalent to;
>
> % cp src1 src2 ... srcN target
>
> This makes cp work with xargs;
>
> % cat ReallyBigListOfFiles | xargs cp -d target
>
> -Brian
>
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--
> Captain Hook died of jock itch.
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