•Re: Grep - print matched line and next N lines

I think your basic logic is overkill and prone to initial bugs, or maintenance bugs, because you're reading in two places, and testing in two places, and generally saying things twice. That's always a bad sign. Just do this:

$n = 0;
while (<>) {
  $n = 7 if /$pattern/; # start printing
  if ($n) { print; $n-- } # print if within
  $n = 0 if eof; # don't leak across file boundaries
}
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Plus or minus a few parameters, of course.

-- Randal L. Schwartz, Perl hacker

Comment on •Re: Grep - print matched line and next N lines Download Code

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Re: •Re: Grep - print matched line and next N lines by runrig (Abbot) on Aug 13, 2002 at 17:23 UTC
Well, I'm all for making things simpler, so I've updated it with your suggestion (and keeping all the previous parameters intact). I was a little concerned about testing for eof on every iteration, but it doesn't really make that big of a difference. And I think doing it this way makes it easier to add more options, like setting different 'after' counts for different patterns and such.	[reply]