[svlug] Re: [svlug]how to copy a bunch of "." files?

[Tin Le]

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> I'd tend to agree with you here. The info pages on find(1) seem to
> support this -- and using the exec flag to grep through something
> like the linux source tree takes a lot longer than it does using
> xargs on my system. 

> But based on what you said, I'd expect to see a forest of grep
> processes running, one per source file in the linux source tree, all
> looking for something (for the test, I looked in all source files for
> the word 'panic'). I did not notice anything forking new processes,
> despite repeated utterances of 'ps alx'. But it took substantially
> longer, with more think time at the start of the process than with
> an xargs solution.

Modern find serializes -exec in a directory.  I've never work on find
source so don't know the exact alg used, but I distinctly remember
shooting myself in the foot ;-) with "find -exec" on an early *NIX
system about 15 years ago.  I think it might have been System III.
That particular find command tried to "optimize" its work by creating
multiple childprocs to handle subdirs (one per subdir), and I had a
fairly deep and wide source tree, which quickly overwhelmed the poor
3B2 I was on.  Pissed off a lot of people in my dept...

That 3B2 had all of 1MB of RAM and a 10MB drive, shared by 30 people.

> Furthermore, the xargs gives the data in a better presentation: the
> find -exec doesn't give the filenames, but the xargs does (using
> find . -name "*.[ch] | xargs grep 'panic' -).

You could use -print with find to get filenames.  Find is kind of like
the kitchen sink command, many options and lots of things you can use it
for.

Tin Le

- ----
http://tin.le.org
Internet Security and Firewall Consulting
Tin Le - tin at le.org


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