GNU bug report logs - #18266
grep -P and invalid exits with error

Previous Next

Full log

View this message in rfc822 format

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Vincent Lefevre <vincent <at> vinc17.net>
Cc: 18266 <at> debbugs.gnu.org, 758105 <at> bugs.debian.org
Subject: bug#18266: handling bytes not part of the charset, and other garbage
Date: Fri, 12 Sep 2014 17:57:39 -0700

Vincent Lefevre wrote:
> I wonder whether anyone is interested in matching individual bytes
> in a file regarded as UTF-8 encoded. This seems weird.

It's not weird at all.  For example, suppose we invent the notation 
[[:error:]] to match encoding errors.  Then the pattern '[[:error:]]' 
would match all encoding errors in a file, which could well be a useful 
thing.

Currently, for example, the tz package <http://www.iana.org/time-zones> 
has a Make rule 'check_character_set' that verifies that the source 
files are all properly encoded.  It executes this shell command:

! grep -nv '^.*$' file names

This relies on GNU grep's behavior that "." does not match an encoding 
error.  But it's a command that is not obvious.  It'd be simpler and 
clearer to write this:

! grep -n '[[:error:]]' file names

if such a feature were available.

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.