Date: Thu, 23 Jan 2014 15:42:16 -0700 (MST) From: Warren Block <wblock@wonkity.com> To: "'Devin Teske'" <dteske@FreeBSD.org> Cc: 'RW' <rwmaillists@googlemail.com>, freebsd-questions@freebsd.org Subject: RE: awk programming question Message-ID: <alpine.BSF.2.00.1401231537260.80613@wonkity.com> In-Reply-To: <04aa01cf187e$cfcf9ef0$6f6edcd0$@FreeBSD.org> References: <F01EB9CE742DEB17DB6B51C7@localhost> <alpine.BSF.2.00.1401230900270.76961@wonkity.com> <20140123185604.4cbd7611@gumby.homeunix.com> <04a201cf1878$8ebce540$ac36afc0$@FreeBSD.org> <alpine.BSF.2.00.1401231346520.80613@wonkity.com> <04aa01cf187e$cfcf9ef0$6f6edcd0$@FreeBSD.org>
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On Thu, 23 Jan 2014, dteske@FreeBSD.org wrote:
>
>
>> -----Original Message-----
>> From: Warren Block [mailto:wblock@wonkity.com]
>> Sent: Thursday, January 23, 2014 12:57 PM
>> To: 'Devin Teske'
>> Cc: 'RW'; freebsd-questions@freebsd.org
>> Subject: RE: awk programming question
>>
>> On Thu, 23 Jan 2014, dteske@FreeBSD.org wrote:
>>
>>>> From: RW [mailto:rwmaillists@googlemail.com]
>>>> Note that awk supports +, but not newfangled things like *.
>>>
>>> With respect to regex, what awk really needs is the quantifier syntax...
>>>
>>> * = {0,} = zero or more
>>> + = {1,} = one or more
>>> {x,y} = any quantity from x inclusively up to y {x,} = any quantity
>>> from x or more
>>
>> I think RW meant to type that awk did not have the newfangled "?" for non-
>> greedy matches.
>
> But that one is supported. Tested on 9.2-R and 10.0-R...
>
> echo abbb | awk '{sub(/a?bbb/, ""); print}' # produces NULL output
> echo bbb | awk '{sub(/a?bbb/, ""); print}' # similarly produces NULL output
>
> Seems to be supported. But I'd really like to see {x,y} (the ? is equivalent
> to {0,1}).
No, the non-greedy modifier to a standard quantifier:
echo "abczabczabcz" | perl -ne '/(a.*z)/; print "$1\n"'
abczabczabcz
echo "abczabczabcz" | perl -ne '/(a.*?z)/; print "$1\n"'
abcz
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