perlpie only on files with affected contents

stabu has asked for the wisdom of the Perl Monks concerning the following question:

Hi!

Im not a perl programmer, but am partial to a specific command line invocation, which I think is fairly well known, namely, in my "letter directory" where I keep my love letter files I do a:

perl -p -i -e 's!oldgirlfriendname!newgirlfriendname!g' *
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Yes, fairly self-explanatory and ruthless, I should think.

HOWEVER, the directory has a bunch of other letters which have nothing to do with my girlfriends. However, the above command line, actually changes the modification date on those too, even if no text has been replaced.

Does anybody know a version of this command line invocation where the files not affected by the replacement retain their original modification date?

Thanks in adv.

Comment on perlpie only on files with affected contents Download Code

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•Re: perlpie only on files with affected contents
by merlyn (Sage) on Apr 29, 2004 at 16:37 UTC

#!/usr/bin/perl
$^I = ".bak";
@ARGV = glob "*";
while (<>) {
  s/old/new/ and $changes = 1;
  print;
  if (eof) { # retreat if no changes:
    rename "$ARGV$^I", $ARGV unless $changes;
    $changes = 0; # reset
  }
}
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-- Randal L. Schwartz, Perl hacker
Be sure to read my standard disclaimer if this is a reply.

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Re: •Re: perlpie only on files with affected contents

by stabu (Scribe) on Apr 29, 2004 at 16:48 UTC

Thanks for really fast replies! Much appreciated. I take note of the caveat too.

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Re: perlpie only on files with affected contents
by Plankton (Vicar) on Apr 29, 2004 at 16:31 UTC

$ perl -p -i -e 's!oldgirlfriendname!newgirlfriendname!g' `grep -l old
+girlfriend *`
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Plankton: 1% Evil, 99% Hot Gas.

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Re: perlpie only on files with affected contents
by EdwardG (Vicar) on Apr 29, 2004 at 16:39 UTC

grep -il amanda * | xargs perl -p -i.bak -e "s!amanda!barbie!ig"
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Re: perlpie only on files with affected contents
by halley (Prior) on Apr 29, 2004 at 16:36 UTC

.bashrc

--
[ e d @ h a l l e y . c c ]

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Re: perlpie only on files with affected contents
by graff (Chancellor) on Apr 29, 2004 at 21:59 UTC

The same concern could apply to the string substitutions that you do: you should perhaps be careful to set it up like so:

s!\boldgirlfriendname\b!newgirlfriendname!g
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