in reply to Myth busted: Shell isn't always faster than Perl

The problem with the shell version is that it's spawning a new process for every rm. The usual practice is to use xargs in conjunction with find. 
time find . -type f -print | xargs rm

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I don't know how much that will affect your timings, though.
Caution: Contents may have been coded under pressure.

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Re^2: Myth busted: Shell isn't always faster than Perl
by jdhedden (Deacon) on Dec 30, 2005 at 20:36 UTC
    I'd say it's a wash. Trying it several times, the best times I got were: 
    time perl -MFile::Find -e'finddepth sub { unlink if -f }, @ARGV' /tmp

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    real    0m3.111s
user    0m0.821s
sys     0m2.233s

    time find /tmp -type f | xargs rm

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    real    0m3.312s
user    0m0.760s
sys     0m2.511s
    And the varied widely - anywhere up to 5 seconds.
    Remember: There's always one more bug.
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      I tested my original script with the 
      return if -d;
unlink $_

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      against the golfed 
      unlink $_ if -f;

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      and the golfed -f test seems to be a bit slower. Maybe because unlink somehow gets called for each directory then stopped? Whereas the 'return if -d ' returns immediately. BUT the improved shell with null 
      find . -type f -print0 | xargs -0 rm

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      seems to win :-( 
      time -d-test Gtk3 
  real    0m0.412s
  user    0m0.074s
  sys     0m0.337s

time -f-test Gtk3 
  real    0m0.478s
  user    0m0.076s
  sys     0m0.388s

time find . -type f -print0 | xargs -0 rm
real    0m0.334s
user    0m0.012s
sys     0m0.321s

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      I'm not really a human, but I play one on earth. flash japh
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Re^2: Myth busted: Shell isn't always faster than Perl
by zentara (Cardinal) on Dec 30, 2005 at 20:16 UTC
    Yeah, that brings the shell closer in speed, BUT it starts complaining AND skipping filenames with spaces in them, I believe that is why the original contruct was the way it was.
    I'm not really a human, but I play one on earth. flash japh
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      it starts complaining AND skipping filenames with spaces in them

      ...And that is precisely why find has the -print0 switch and xargs has the -0 (or --null) switch. 

      find . -type f -print0 | xargs -0 rm

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      We're building the house of the future together.
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        This leaves the problem of a very big list, in which case the shell (I presume) would refuse to start the xargs side.

        Flavio
        perl -ple'$_=reverse' <<<ti.xittelop@oivalf

        Don't fool yourself.
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