GNU bug report logs - #68989
grep -m[2+] > /dev/null

Package: grep;

Reported by: Grisha Levit <grishalevit <at> gmail.com>

Date: Thu, 8 Feb 2024 08:39:01 UTC

Severity: normal

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Report forwarded to bug-grep <at> gnu.org:
bug#68989; Package grep. (Thu, 08 Feb 2024 08:39:01 GMT) Full text and rfc822 format available.

Acknowledgement sent to Grisha Levit <grishalevit <at> gmail.com>:
New bug report received and forwarded. Copy sent to bug-grep <at> gnu.org. (Thu, 08 Feb 2024 08:39:01 GMT) Full text and rfc822 format available.

Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Grisha Levit <grishalevit <at> gmail.com>
To: bug-grep <at> gnu.org
Subject: grep -m[2+] > /dev/null
Date: Thu, 8 Feb 2024 03:37:24 -0500

[Message part 1 (text/plain, inline)]

This example file will require multiple reads:

$ printf '%07d\n' {0..98304} > txt

When limiting the match count to 1, the input offset is correctly restored
before grep exits,  no matter the output:

$ { grep -m1 . >/dev/zero; head -n1; } < txt
0000001
$ { grep -m1 . >/dev/null; head -n1; } < txt
0000001

If the count is 2 or higher, this also works, unless the output is being
discarded to /dev/null -- in this case not only is the input offset not
restored, but the entire file is consumed:

$ { grep -m2 . >/dev/zero; head -n1; } < txt
0000002
$ { grep -m2 . >/dev/null; head -n1; } < txt
$

[Message part 2 (text/html, inline)]

Reply sent to Paul Eggert <eggert <at> cs.ucla.edu>:
You have taken responsibility. (Fri, 09 Feb 2024 09:09:02 GMT) Full text and rfc822 format available.

Notification sent to Grisha Levit <grishalevit <at> gmail.com>:
bug acknowledged by developer. (Fri, 09 Feb 2024 09:09:02 GMT) Full text and rfc822 format available.

Message #10 received at 68989-done <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Grisha Levit <grishalevit <at> gmail.com>
Cc: 68989-done <at> debbugs.gnu.org
Subject: Re: bug#68989: grep -m[2+] > /dev/null
Date: Fri, 9 Feb 2024 01:08:24 -0800

[Message part 1 (text/plain, inline)]

Thanks for the bug report. I installed the attached patch; please give 
it a try.

[0001-grep-fix-grep-m2-pattern-file-dev-null.patch (text/x-patch, attachment)]

bug archived. Request was from Debbugs Internal Request <help-debbugs <at> gnu.org> to internal_control <at> debbugs.gnu.org. (Fri, 08 Mar 2024 12:24:10 GMT) Full text and rfc822 format available.

Did not alter fixed versions and reopened. Request was from Debbugs Internal Request <help-debbugs <at> gnu.org> to internal_control <at> debbugs.gnu.org. (Mon, 13 May 2024 07:24:01 GMT) Full text and rfc822 format available.

bug unarchived. Request was from Paul Eggert <eggert <at> cs.ucla.edu> to control <at> debbugs.gnu.org. (Mon, 13 May 2024 07:26:02 GMT) Full text and rfc822 format available.

Information forwarded to bug-grep <at> gnu.org:
bug#68989; Package grep. (Mon, 13 May 2024 07:28:02 GMT) Full text and rfc822 format available.

Message #21 received at 68989 <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Grisha Levit <grishalevit <at> gmail.com>
Cc: 68989 <at> debbugs.gnu.org
Subject: Re: bug#68989: grep -m[2+] > /dev/null
Date: Mon, 13 May 2024 00:27:19 -0700

On 2024-05-12 22:26, Grisha Levit wrote:

> Just noticed that with this patch grep has extra output when -m is used
> with -[lLq]:
> 
>      $ echo x | grep -l -m1 .
>      x
>      (standard input)
> 
>      $ echo x | grep -q -m1 .
>      x

Thanks for letting us know; I've reopened the bug report.

This bug report was last modified 1 year and 33 days ago.

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GNU bug report logs - #68989 grep -m[2+] > /dev/null

GNU bug report logs - #68989
grep -m[2+] > /dev/null