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Re: bin/43896: grep -o match problem
The following reply was made to PR bin/43896; it has been noted by GNATS.
From: David Holland <dholland-bugs%netbsd.org@localhost>
Subject: Re: bin/43896: grep -o match problem
Date: Mon, 27 Sep 2010 02:17:47 +0000
On Wed, Sep 22, 2010 at 03:55:00PM +0000, peter%kerwien.homeip.net@localhost
> The following command fails to match properly:
> echo VERSION=10 | grep -o '[0-9]*'
> The result is empty. The correct result should be 10.
This result is, though perhaps not useful, correct. You can see what's
going on if you try sed:
% echo VERSION=10 | sed 's/[0-9]*/wibble/'
Because [0-9]* matches the empty string, grep is matching the empty
string at the beginning of the line and printing that.
To get the result you're looking for, try grep -o '[0-9][0-9]*' or
egrep -o '[0-9]+'.
David A. Holland
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