From unknown Wed Jun 18 23:11:24 2025 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-Mailer: MIME-tools 5.509 (Entity 5.509) Content-Type: text/plain; charset=utf-8 From: bug#21865 <21865@debbugs.gnu.org> To: bug#21865 <21865@debbugs.gnu.org> Subject: Status: Parenthesis subexpressions Reply-To: bug#21865 <21865@debbugs.gnu.org> Date: Thu, 19 Jun 2025 06:11:24 +0000 retitle 21865 Parenthesis subexpressions reassign 21865 grep submitter 21865 Valerio Bozzolan severity 21865 wishlist thanks From debbugs-submit-bounces@debbugs.gnu.org Sun Nov 08 16:57:06 2015 Received: (at submit) by debbugs.gnu.org; 8 Nov 2015 21:57:06 +0000 Received: from localhost ([127.0.0.1]:57896 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1ZvXxR-00072d-Aq for submit@debbugs.gnu.org; Sun, 08 Nov 2015 16:57:05 -0500 Received: from eggs.gnu.org ([208.118.235.92]:57371) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1ZvXC9-0005uT-TZ for submit@debbugs.gnu.org; Sun, 08 Nov 2015 16:08:33 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZvXC8-0000hP-QU for submit@debbugs.gnu.org; Sun, 08 Nov 2015 16:08:13 -0500 X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on eggs.gnu.org X-Spam-Level: *** X-Spam-Status: No, score=3.3 required=5.0 tests=BAYES_50,HTML_MESSAGE, RECEIVED_FROM_WINDOWS_HOST autolearn=disabled version=3.3.2 Received: from lists.gnu.org ([2001:4830:134:3::11]:59822) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZvXC8-0000hE-NU for submit@debbugs.gnu.org; Sun, 08 Nov 2015 16:08:12 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39133) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZvXC7-00018x-R6 for bug-grep@gnu.org; Sun, 08 Nov 2015 16:08:12 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZvXC4-0000dv-Ay for bug-grep@gnu.org; Sun, 08 Nov 2015 16:08:11 -0500 Received: from bagheera.educ.di.unito.it ([130.192.157.8]:38407) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZvXC3-0000dW-WD for bug-grep@gnu.org; Sun, 08 Nov 2015 16:08:08 -0500 Received: from service.labinfo.educ.di.unito.it (service [130.192.157.3]) by bagheera.educ.di.unito.it (FRW-EDUC-INFODIP) with ESMTP id tA8KhW3Z010266 for ; Sun, 8 Nov 2015 21:43:33 +0100 (CET) Received: from android-12971102cb783e32 (host197-171-dynamic.233-95-r.retail.telecomitalia.it [95.233.171.197] (may be forged)) (authenticated bits=0) by service.labinfo.educ.di.unito.it (8.14.4/8.14.4) with ESMTP id tA8KhSBV029586 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Sun, 8 Nov 2015 21:43:29 +0100 (CET) User-Agent: K-9 Mail for Android MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----NX6JLVEXP41ZA2PIJXJH49U54QQYBR" Content-Transfer-Encoding: 8bit Subject: Parenthesis subexpressions From: Valerio Bozzolan Date: Sun, 08 Nov 2015 21:42:44 +0100 To: bug-grep@gnu.org Message-ID: X-AntiVirus: Scanned for viruses by VirusFinder @2001-tecnici@educ.di.unito.it - Email Clean X-SpamCheck: not spam X-MailScanner-From: bozzolan.valerio@educ.di.unito.it X-detected-operating-system: by eggs.gnu.org: Windows NT kernel [generic] [fuzzy] X-detected-operating-system: by eggs.gnu.org: Error: Malformed IPv6 address (bad octet value). X-Received-From: 2001:4830:134:3::11 X-Spam-Score: -4.1 (----) X-Debbugs-Envelope-To: submit X-Mailman-Approved-At: Sun, 08 Nov 2015 16:57:03 -0500 X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: -4.1 (----) ------NX6JLVEXP41ZA2PIJXJH49U54QQYBR Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Hi, (First time in a GNU mailing list!) I've already asked this question to my local GNU/Linux user group and in #grep@Freenode... I'm still confused. GNU Grep don't have an arg to choose the subexpression. Right? Stupid e.g.: echo abcde | grep -o -E 'b([a-z])d' => "bcd" What if I want the first subexpression? ("b")? GNU Grep can't do it. Isn't it? (Why?) I actually use GNU Awk, or GNU Bash with $BASH_REMATCH[$n_sub]. Thank you for the clarification! -- Valerio Bozzolan Email sent from Android (CyanogenMod) using K-9 Mail. ------NX6JLVEXP41ZA2PIJXJH49U54QQYBR Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: 8bit Hi,

(First time in a GNU mailing list!)

I've already asked this question to my local GNU/Linux user group and in #grep@Freenode... I'm still confused.

GNU Grep don't have an arg to choose the subexpression. Right?

Stupid e.g.:
echo abcde | grep -o -E 'b([a-z])d'
=> "bcd"

What if I want the first subexpression? ("b")? GNU Grep can't do it. Isn't it? (Why?)

I actually use GNU Awk, or GNU Bash with $BASH_REMATCH[$n_sub].

Thank you for the clarification!
--
Valerio Bozzolan
Email sent from Android (CyanogenMod) using K-9 Mail. ------NX6JLVEXP41ZA2PIJXJH49U54QQYBR-- From debbugs-submit-bounces@debbugs.gnu.org Sun Nov 08 17:35:40 2015 Received: (at submit) by debbugs.gnu.org; 8 Nov 2015 22:35:40 +0000 Received: from localhost ([127.0.0.1]:57921 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1ZvYYT-0007y4-AS for submit@debbugs.gnu.org; Sun, 08 Nov 2015 17:35:40 -0500 Received: from eggs.gnu.org ([208.118.235.92]:57372) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1ZvXC9-0005uV-UQ for submit@debbugs.gnu.org; Sun, 08 Nov 2015 16:08:33 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZvXC9-0000hX-18 for submit@debbugs.gnu.org; Sun, 08 Nov 2015 16:08:13 -0500 X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on eggs.gnu.org X-Spam-Level: *** X-Spam-Status: No, score=3.3 required=5.0 tests=BAYES_50,HTML_MESSAGE, RECEIVED_FROM_WINDOWS_HOST autolearn=disabled version=3.3.2 Received: from lists.gnu.org ([2001:4830:134:3::11]:44005) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZvXC8-0000hT-UP for submit@debbugs.gnu.org; Sun, 08 Nov 2015 16:08:12 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39134) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZvXC7-00018y-RF for bug-grep@gnu.org; Sun, 08 Nov 2015 16:08:12 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZvXC5-0000eC-4U for bug-grep@gnu.org; Sun, 08 Nov 2015 16:08:11 -0500 Received: from bagheera.educ.di.unito.it ([130.192.157.8]:38407) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZvXC4-0000dW-OL for bug-grep@gnu.org; Sun, 08 Nov 2015 16:08:09 -0500 Received: from service.labinfo.educ.di.unito.it (service [130.192.157.3]) by bagheera.educ.di.unito.it (FRW-EDUC-INFODIP) with ESMTP id tA8KnqPq010302 for ; Sun, 8 Nov 2015 21:49:52 +0100 (CET) Received: from android-12971102cb783e32 (host197-171-dynamic.233-95-r.retail.telecomitalia.it [95.233.171.197] (may be forged)) (authenticated bits=0) by service.labinfo.educ.di.unito.it (8.14.4/8.14.4) with ESMTP id tA8Knl61029917 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Sun, 8 Nov 2015 21:49:49 +0100 (CET) User-Agent: K-9 Mail for Android In-Reply-To: References: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----20WOICGV4HQVLHDL12S12HCQDMPG8T" Content-Transfer-Encoding: 8bit Subject: Re: Parenthesis subexpressions From: Valerio Bozzolan Date: Sun, 08 Nov 2015 21:49:03 +0100 To: bug-grep@gnu.org Message-ID: <26C5964E-1809-4066-B3B7-CBC4A1C081A9@educ.di.unito.it> X-AntiVirus: Scanned for viruses by VirusFinder @2001-tecnici@educ.di.unito.it - Email Clean X-SpamCheck: not spam X-MailScanner-From: bozzolan.valerio@educ.di.unito.it X-detected-operating-system: by eggs.gnu.org: Windows NT kernel [generic] [fuzzy] X-detected-operating-system: by eggs.gnu.org: Error: Malformed IPv6 address (bad octet value). X-Received-From: 2001:4830:134:3::11 X-Spam-Score: -4.1 (----) X-Debbugs-Envelope-To: submit X-Mailman-Approved-At: Sun, 08 Nov 2015 17:35:19 -0500 X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: -4.1 (----) ------20WOICGV4HQVLHDL12S12HCQDMPG8T Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Sorry... typo... echo abcde | grep -o -E 'b([a-z])d' => "bcd" Can't I choose to have only "c"? Thanks again! On 8 November 2015 21:42:44 CET, Valerio Bozzolan wrote: >Hi, > >(First time in a GNU mailing list!) > >I've already asked this question to my local GNU/Linux user group and >in #grep@Freenode... I'm still confused. > >GNU Grep don't have an arg to choose the subexpression. Right? > >Stupid e.g.: > echo abcde | grep -o -E 'b([a-z])d' > => "bcd" > >What if I want the first subexpression? ("b")? GNU Grep can't do it. >Isn't it? (Why?) > >I actually use GNU Awk, or GNU Bash with $BASH_REMATCH[$n_sub]. > >Thank you for the clarification! >-- >Valerio Bozzolan >Email sent from Android (CyanogenMod) using K-9 Mail. -- Valerio Bozzolan Email sent from Android (CyanogenMod) using K-9 Mail. http://boz.reyboz.it ------20WOICGV4HQVLHDL12S12HCQDMPG8T Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: 8bit Sorry... typo...

echo abcde | grep -o -E 'b([a-z])d'
=> "bcd"

Can't I choose to have only "c"?

Thanks again!

On 8 November 2015 21:42:44 CET, Valerio Bozzolan <bozzolan.valerio@educ.di.unito.it> wrote:
Hi,

(First time in a GNU mailing list!)

I've already asked this question to my local GNU/Linux user group and in #grep@Freenode... I'm still confused.

GNU Grep don't have an arg to choose the subexpression. Right?

Stupid e.g.:
echo abcde | grep -o -E 'b([a-z])d'
=> "bcd"

What if I want the first subexpression? ("b")? GNU Grep can't do it. Isn't it? (Why?)

I actually use GNU Awk, or GNU Bash with $BASH_REMATCH[$n_sub].

Thank you for the clarification!
--
Valerio Bozzolan
Email sent from Android (CyanogenMod) using K-9 Mail.

--
Valerio Bozzolan
Email sent from Android (CyanogenMod) using K-9 Mail.

http://boz.reyboz.it ------20WOICGV4HQVLHDL12S12HCQDMPG8T-- From debbugs-submit-bounces@debbugs.gnu.org Mon Nov 09 08:51:09 2015 Received: (at 21865) by debbugs.gnu.org; 9 Nov 2015 13:51:09 +0000 Received: from localhost ([127.0.0.1]:58325 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1Zvmqi-0007aT-Pc for submit@debbugs.gnu.org; Mon, 09 Nov 2015 08:51:09 -0500 Received: from mail-wm0-f50.google.com ([74.125.82.50]:35779) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1ZvmqO-0007Zk-Nn for 21865@debbugs.gnu.org; Mon, 09 Nov 2015 08:51:07 -0500 Received: by wmdw130 with SMTP id w130so30261890wmd.0 for <21865@debbugs.gnu.org>; Mon, 09 Nov 2015 05:50:47 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:content-transfer-encoding :in-reply-to:user-agent; bh=JW9TXqfAh1CanYNfPUrid5w3AA1DML5YlCB/ZGWjkZ0=; b=aj4C/dfDXv9rQeFKaulo0lAbJuA0RR4S10zjHPR8M27xlQKJXHF/mvOQlwLxez275r P/h+tCqSXT31fr9y2hv5pJTNR+Gq7PWwcT4KUwOufjfpboLy3C//VgvRXEnYUvPJVews CwIkk/nV6ZpPdQ9ZBeqfRRQBhfXRjSL/1KLntGJhVzj01vtVuVrgmK33jjurYV+eUKKa fWZOJ23mRBWa4538hoVHERzQEJzJK2U6aEbq2T4x7sHNdaC7F2IrCxZK0VucFaeRszAz fz10nk8IX7ImZMb/Q6l6jMCTqxQfQJorzpZ/ylnNUb2cJdL7bNkeAg5o/+iyhLhMKr3S FzKA== X-Received: by 10.28.47.8 with SMTP id v8mr10525384wmv.30.1447077047774; Mon, 09 Nov 2015 05:50:47 -0800 (PST) Received: from chaz.gmail.com (05421d95.skybroadband.com. [5.66.29.149]) by smtp.gmail.com with ESMTPSA id s2sm14431637wmd.13.2015.11.09.05.50.46 (version=TLSv1.2 cipher=RC4-SHA bits=128/128); Mon, 09 Nov 2015 05:50:46 -0800 (PST) Date: Mon, 9 Nov 2015 13:50:46 +0000 From: Stephane Chazelas To: Valerio Bozzolan Subject: Re: bug#21865: Parenthesis subexpressions Message-ID: <20151109135045.GA9675@chaz.gmail.com> References: <26C5964E-1809-4066-B3B7-CBC4A1C081A9@educ.di.unito.it> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <26C5964E-1809-4066-B3B7-CBC4A1C081A9@educ.di.unito.it> User-Agent: Mutt/1.5.21 (2010-09-15) X-Spam-Score: 0.0 (/) X-Debbugs-Envelope-To: 21865 Cc: 21865@debbugs.gnu.org X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: 0.0 (/) 2015-11-08 21:49:03 +0100, Valerio Bozzolan: > Sorry... typo... > > echo abcde | grep -o -E 'b([a-z])d' > => "bcd" > > Can't I choose to have only "c"? [...] That's correct, GNU grep doesn't have that capability (yet). Recent versions of pcregrep do: $ echo abc | pcregrep -o1 '.(.).' b Now, I'm not a GNU grep maintainer but I suppose the question is how far do we want to take grep away from its original purpose (print the lines that match a pattern which is what g/re/p stands for). GNU grep is already doing find's job with -r, part of sed's job with -o/--colour. Having said that, I do agree it's the logical continuation after -o. Note that for now, you can already do: $ echo abcde | grep -o -P 'b\K[a-z](?=d)' c -- Stephane From debbugs-submit-bounces@debbugs.gnu.org Mon Nov 09 11:04:06 2015 Received: (at 21865) by debbugs.gnu.org; 9 Nov 2015 16:04:06 +0000 Received: from localhost ([127.0.0.1]:59381 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1ZvovO-0002Yw-0E for submit@debbugs.gnu.org; Mon, 09 Nov 2015 11:04:06 -0500 Received: from bagheera.educ.di.unito.it ([130.192.157.8]:48676) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1ZvovL-0002YV-7t for 21865@debbugs.gnu.org; Mon, 09 Nov 2015 11:04:04 -0500 Received: from service.labinfo.educ.di.unito.it (service [130.192.157.3]) by bagheera.educ.di.unito.it (FRW-EDUC-INFODIP) with ESMTP id tA9G3m72019378 for <21865@debbugs.gnu.org>; Mon, 9 Nov 2015 17:03:48 +0100 (CET) Received: from android-12971102cb783e32 (host126-88-dynamic.244-95-r.retail.telecomitalia.it [95.244.88.126]) (authenticated bits=0) by service.labinfo.educ.di.unito.it (8.14.4/8.14.4) with ESMTP id tA9G3hQR001086 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for <21865@debbugs.gnu.org>; Mon, 9 Nov 2015 17:03:44 +0100 (CET) User-Agent: K-9 Mail for Android In-Reply-To: <20151109135045.GA9675@chaz.gmail.com> References: <26C5964E-1809-4066-B3B7-CBC4A1C081A9@educ.di.unito.it> <20151109135045.GA9675@chaz.gmail.com> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----V1N35ZTS6BAUF5FX59QO5T3ANXJ7IU" Content-Transfer-Encoding: 8bit Subject: Re: bug#21865: Parenthesis subexpressions From: Valerio Bozzolan Date: Mon, 09 Nov 2015 17:03:39 +0100 Message-ID: X-AntiVirus: Scanned for viruses by VirusFinder @2001-tecnici@educ.di.unito.it - Email Clean X-SpamCheck: not spam X-MailScanner-From: bozzolan.valerio@educ.di.unito.it X-Spam-Score: 0.9 (/) X-Debbugs-Envelope-To: 21865 Cc: 21865@debbugs.gnu.org X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: 0.9 (/) ------V1N35ZTS6BAUF5FX59QO5T3ANXJ7IU Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Thanks for agreeing with the evolution of the meaning of "-o". Just to make you a laugh: I was reproducing egrep with $BASH_REMATCH: https://gist.github.com/valerio-bozzolan/6787675e931dce1ba7e9 Definitely not beautiful... but really effective for me. So something like "egrep -o $n regex" also can save the world from code similar to mine. On 9 November 2015 14:50:46 CET, Stephane Chazelas wrote: >2015-11-08 21:49:03 +0100, Valerio Bozzolan: >> Sorry... typo... >> >> echo abcde | grep -o -E 'b([a-z])d' >> => "bcd" >> >> Can't I choose to have only "c"? >[...] > >That's correct, GNU grep doesn't have that capability (yet). >Recent versions of pcregrep do: > >$ echo abc | pcregrep -o1 '.(.).' >b > >Now, I'm not a GNU grep maintainer but I suppose the question is >how far do we want to take grep away from its original purpose >(print the lines that match a pattern which is what g/re/p >stands for). > >GNU grep is already doing find's job with -r, part of sed's job >with -o/--colour. > >Having said that, I do agree it's the logical continuation after >-o. > >Note that for now, you can already do: > >$ echo abcde | grep -o -P 'b\K[a-z](?=d)' >c > > >-- >Stephane -- Valerio Bozzolan Email sent from Android (CyanogenMod) using K-9 Mail. ------V1N35ZTS6BAUF5FX59QO5T3ANXJ7IU Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: 8bit Thanks for agreeing with the evolution of the meaning of "-o".

Just to make you a laugh: I was reproducing egrep with $BASH_REMATCH:
https://gist.github.com/valerio-bozzolan/6787675e931dce1ba7e9

Definitely not beautiful... but really effective for me.

So something like "egrep -o $n regex" also can save the world from code similar to mine.

On 9 November 2015 14:50:46 CET, Stephane Chazelas <stephane.chazelas@gmail.com> wrote:
2015-11-08 21:49:03 +0100, Valerio Bozzolan:
 Sorry... typo...
 
     echo abcde | grep -o -E 'b([a-z])d'
     => "bcd"
 
 Can't I choose to have only "c"?
[...]

That's correct, GNU grep doesn't have that capability (yet).
Recent versions of pcregrep do:

$ echo abc | pcregrep -o1 '.(.).'
b

Now, I'm not a GNU grep maintainer but I suppose the question is
how far do we want to take grep away from its original purpose
(print the lines that match a pattern which is what g/re/p
stands for).

GNU grep is already doing find's job with -r, part of sed's job
with -o/--colour.

Having said that, I do agree it's the logical continuation after
-o.

Note that for now, you can already do:

$ echo!
  abcde |
grep -o -P 'b\K[a-z](?=d)'
c


--
Valerio Bozzolan
Email sent from Android (CyanogenMod) using K-9 Mail. ------V1N35ZTS6BAUF5FX59QO5T3ANXJ7IU-- From debbugs-submit-bounces@debbugs.gnu.org Mon Nov 09 12:27:04 2015 Received: (at 21865) by debbugs.gnu.org; 9 Nov 2015 17:27:04 +0000 Received: from localhost ([127.0.0.1]:59412 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1ZvqDg-0004W1-00 for submit@debbugs.gnu.org; Mon, 09 Nov 2015 12:27:04 -0500 Received: from mail-wm0-f54.google.com ([74.125.82.54]:34420) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1ZvqDM-0004VK-3v for 21865@debbugs.gnu.org; Mon, 09 Nov 2015 12:27:03 -0500 Received: by wmnn186 with SMTP id n186so116595187wmn.1 for <21865@debbugs.gnu.org>; Mon, 09 Nov 2015 09:26:43 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=resent-from:resent-date:resent-message-id:resent-to:date:from:to :subject:message-id:references:mime-version:content-type :content-disposition:in-reply-to:user-agent; bh=DQL65UHwea4FcWN69KFRfRLMi5HTbJNQjFWBqkfc6Tc=; b=zLj7/J+j893fkmZNnQeFMrMSKzAPSEkA3cR9XqlpRQp4IT2VHCGoFXhWk8cq+bU8B/ 3kzvMmFcfNjVSCw5hh03ESJXA4q17DeaVlrZaRJHQdiA12OYSwoucdf8T7Tb39vKbvGx eoEDb2zy45EADXGyIv/s0BSJORGbCcii7RX7AN3wL2eeGDRav4mHytfT2VoHAoeT3TEM Y+aggHL07GTCDCBpdYgOW61XWtOECBIkuK4HtBGj6VjXAKNCBfSDDDJsjqhzGH0Zc73Q MTtEa2ybv47G3y6FF106BPHYnr8uSesRs3lNoLZV+ydEnn7FdGU6ob3di3qtap/HQPtj zdCQ== X-Received: by 10.194.7.97 with SMTP id i1mr35803364wja.87.1447090003219; Mon, 09 Nov 2015 09:26:43 -0800 (PST) Received: from chaz.gmail.com (05421d95.skybroadband.com. [5.66.29.149]) by smtp.gmail.com with ESMTPSA id 71sm15330750wmm.24.2015.11.09.09.26.42 for <21865@debbugs.gnu.org> (version=TLSv1.2 cipher=RC4-SHA bits=128/128); Mon, 09 Nov 2015 09:26:43 -0800 (PST) Resent-From: Stephane Chazelas Resent-Date: Mon, 9 Nov 2015 17:26:42 +0000 Resent-Message-ID: <20151109172642.GA14624@chaz.gmail.com> Resent-To: 21865@debbugs.gnu.org Date: Mon, 9 Nov 2015 17:16:19 +0000 From: Stephane Chazelas To: Valerio Bozzolan Subject: Re: bug#21865: Parenthesis subexpressions Message-ID: <20151109171619.GA9658@chaz.gmail.com> References: <26C5964E-1809-4066-B3B7-CBC4A1C081A9@educ.di.unito.it> <20151109135045.GA9675@chaz.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-Spam-Score: 0.0 (/) X-Debbugs-Envelope-To: 21865 X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: 0.0 (/) 2015-11-09 17:00:36 +0100, Valerio Bozzolan: > Thanks for agreeing with the evolution of the meaning of "-o". > > Just to make you a laugh: I was reproducing egrep with $BASH_REMATCH: > https://gist.github.com/valerio-bozzolan/6787675e931dce1ba7e9 > > Definitely not beautiful... but really effective for me. You may want to read: https://unix.stackexchange.com/questions/169716/why-is-using-a-shell-loop-to-process-text-considered-bad-practice https://unix.stackexchange.com/questions/209123/understand-ifs-read-r-line https://unix.stackexchange.com/questions/65803/why-is-printf-better-than-echo Here, if there wasn't a pcregrep already, I'd rather do it in perl or GNU sed than bash. Like: perl -lne 'print for /a([a-z])c/g' Also note that: echo abac | pcregrep -o1 'a(.)' b c > So something like "egrep -o $n regex" also can save the world from code similar to mine. GNU grep can't add it like that as that would break backward compatibility. grep -o 1 regex file is currently meant to print the occurrences of "1" in the "regex" and "file" files. Even adding it as: grep -o1 regex file would probably not be a good idea as that would mean some ad-hoc parsing of the options (in "grep -o1 regexp", "1" would be an argument to "-o" while in "grep -oi regexp", "i" currently is a separate "-i" option). So reasonably, it should probably be a separate option like -O 1. -- Stephane From debbugs-submit-bounces@debbugs.gnu.org Thu Dec 31 03:55:23 2015 Received: (at control) by debbugs.gnu.org; 31 Dec 2015 08:55:23 +0000 Received: from localhost ([127.0.0.1]:50938 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84) (envelope-from ) id 1aEZ11-0005OJ-J5 for submit@debbugs.gnu.org; Thu, 31 Dec 2015 03:55:23 -0500 Received: from zimbra.cs.ucla.edu ([131.179.128.68]:41868) by debbugs.gnu.org with esmtp (Exim 4.84) (envelope-from ) id 1aEZ0z-0005O1-Ht for control@debbugs.gnu.org; Thu, 31 Dec 2015 03:55:21 -0500 Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id 2C836160ED6 for ; Thu, 31 Dec 2015 00:55:16 -0800 (PST) Received: from zimbra.cs.ucla.edu ([127.0.0.1]) by localhost (zimbra.cs.ucla.edu [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id Dsi6TvFEL1b3 for ; Thu, 31 Dec 2015 00:55:15 -0800 (PST) Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id 4FFD0160ED7 for ; Thu, 31 Dec 2015 00:55:15 -0800 (PST) X-Virus-Scanned: amavisd-new at zimbra.cs.ucla.edu Received: from zimbra.cs.ucla.edu ([127.0.0.1]) by localhost (zimbra.cs.ucla.edu [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id EnJ9ehm4awCT for ; Thu, 31 Dec 2015 00:55:15 -0800 (PST) Received: from [192.168.1.9] (pool-100-32-155-148.lsanca.fios.verizon.net [100.32.155.148]) by zimbra.cs.ucla.edu (Postfix) with ESMTPSA id 3587F160ED6 for ; Thu, 31 Dec 2015 00:55:15 -0800 (PST) To: control@debbugs.gnu.org From: Paul Eggert Subject: grep bug maintenance Organization: UCLA Computer Science Department Message-ID: <5684ED73.6060403@cs.ucla.edu> Date: Thu, 31 Dec 2015 00:55:15 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.4.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Score: -0.0 (/) X-Debbugs-Envelope-To: control X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: -0.0 (/) severity 22059 wishlist severity 21865 wishlist close 22278 close 22279 close 21755 close 21700 tags 21554 wontfix tags 21527 moreinfo