Subject: Re: Repalcement for grep(1)
To: Archie Cobbs <archie@whistle.com>
From: Jamie Howard <howardjp@wam.umd.edu>
List: tech-userlevel
Date: 07/04/1999 21:32:22
Sender: tech-userlevel-owner@netbsd.org
On Sun, 4 Jul 1999, Archie Cobbs wrote:
> There are two special cases- of bracket expressions: the
> bracket expressions `[[:<:]]' and `[[:>:]]' match the null
> string at the beginning and end of a word respectively. A
> word is defined as a sequence of word characters which is
> neither preceded nor followed by word characters. A word
> character is an alnum character (as defined by ctype(3))
> or an underscore. This is an extension, compatible with
> but not specified by POSIX 1003.2, and should be used with
> caution in software intended to be portable to other sys-
> tems.
>
> Perhaps this will help with -w?
Yes, I received a patch from Simon Burge which implements this. It also
beats using [^A-Za-z] and [A-Za-z$] as I was and GNU grep does. I am
still having trouble with -x though. It turns out that even if I specify
a commandline with a pattern of the form "^pattern$", it fails. If I
specify "^pattern" it works. If I specify "pattern$" it does not. I have
yet to find a case where my version will sucessfully match when a $ is at
the end. Has anyone encountered anything like this before?
Jamie
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