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Re: Case insensitivity seems to ignore lower bound of interval

From: Eric Bischoff
Subject: Re: Case insensitivity seems to ignore lower bound of interval
Date: Thu, 28 Apr 2011 15:12:14 +0200
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Le jeudi 28 avril 2011 14:04:28, Davide Brini a écrit :
> But you got me curious. My original test system used mostly vanilla tools
> built from source, so I thought I would try on stock distros instead.
> And guess what, both on a standard RHEL 6 and Debian squeeze, I see your
> results (ie gawk behaves differently).

OK, that's interesting information. That means that either those distributions 
patch the tools, either there's some compilation option that differs.

I have tested 6 stock distros too, all with the same behaviour forgawk (I have 
not tested  sed nor grep  yet).

> Maybe, but my point was that it was no gawk-only bug. But now, having been
> able to reproduce your results, it may well be that gawk does something
> different. Arnold is the authoritative source here.

Yes, and let me take the occasion to thank him for all the great work on gawk 
and the nice documentation.

> > My list of letters in the "echo" part intentionally was stopping at "r"
> > in the grep test, to concentrate on what happens to "r", without
> > influence from what happens to "s".
> If you stop at "r", you won't get any output.
> The only way you would get
> output is if [R-Z] was implemented as "RrSs..." etc., which seems not to
> be the case; rather, it seems to be the other way round ("rRsS..." etc.).


Ah, you were right, grep behaves as awk on this, I did not test thoroughly 

$ echo 'ijklmnopqs' | grep '[R-Z]'
$ echo 'ijklmnopqr' | grep '[R-Z]'

$ echo 'ijklmnopqs' | awk '/[R-Z]/ { print }'
$ echo 'ijklmnopqr' | awk '/[R-Z]/ { print }'

That does not make it more logical :-), and sed is definitely different:
$ echo 'ijklmnopqs' | sed '/[R-Z]/p'
$ echo 'ijklmnopqr' | sed '/[R-Z]/p'
$ echo 'ijklmnopqR' | sed '/[R-Z]/p'
$ echo 'ijklmnopqS' | sed '/[R-Z]/p'

Éric Bischoff - Bureau Cornavin
Technical writing and translations
(+33) 3 68 46 00 85

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