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Message-ID: <E562FCEE3A42D61192880002A5FB4333FF340F@kite.pigroup.co.uk>
From: David Kilroy <david DOT kilroy AT pigroup DOT co DOT uk>
To: "'fergus AT bonhard DOT uklinux DOT net'" <fergus AT bonhard DOT uklinux DOT net>,
   cygwin AT cygwin DOT com
Subject: RE: Cygwin's vanilla sed : capabilities and limitations
Date: Wed, 16 Jul 2003 14:15:12 +0100
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	charset="iso-8859-1"

> -----Original Message-----
> From: fergus AT bonhard DOT uklinux DOT net [mailto:fergus AT bonhard DOT uklinux DOT net]
> 
> Q1. Querying info sed reveals the expression matcher to be "greedy",
> matching the longest possible string. Is there a way to make 
> it match the
> shortest possible, so that echo aaabbbccc | sed 's/^.*b//' 
> (altered but
> similar) grabs aaab not aaabbb?

echo aaabbbccc | sed 's/^[^b]*b//'

but that actually replaces 'aaab' with '', leaving 'bbccc'

echo aaabbbccc | sed 's/b.*$/b/'

will leave you with 'aaab'.

> Q2. Is there a way using the supplied sed without major 
> enhancements to
> change "abc x def" to "def x abc": that is, to grab two 
> distinct portions
> and swap them (using $1,$2 or \1,\2 or whatever).

echo abc x def | sed 's/\(.*\) x \(.*\)/\2 x \1/'

will do the job. Replace the '.*'s with REs that match the side expressions,
and ' x ' with an expression matching your delimiter.

Enjoy

Dave.

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