GNU bug report logs -
#51462
sed bug: ASCII NUL not handled in simple pattern
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bug-sed <at> gnu.org
:
bug#51462
; Package
sed
.
(Thu, 28 Oct 2021 16:49:02 GMT)
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Acknowledgement sent
to
Frances Wingerter <fw <at> immunant.com>
:
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bug-sed <at> gnu.org
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(Thu, 28 Oct 2021 16:49:02 GMT)
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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):
I'm using sed 4.8 (`sed (GNU sed) 4.8` per `sed --version`) on x86_64
Arch Linux.
Compare the output of these two sed invocations:
```
$ echo -e 'a\nb\n\0\nc\n' | sed -e '/\0/,$d'
a
b
c
```
and
```
$ echo -e 'a\nb\n\v\nc\n' | sed -e '/\v/,$d'
a
b
```
The latter is the expected behavior, but when input and pattern use
`\0`, sed seems to miss the matches and never triggers.
Hopefully this should be an easy fix.
Thanks,
Frances
Information forwarded
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bug-sed <at> gnu.org
:
bug#51462
; Package
sed
.
(Thu, 28 Oct 2021 17:33:01 GMT)
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Message #8 received at submit <at> debbugs.gnu.org (full text, mbox):
On Thu, 28 Oct 2021 15:25:42 +0000, Frances Wingerter <fw <at> immunant.com>
wrote:
> I'm using sed 4.8 (`sed (GNU sed) 4.8` per `sed --version`) on x86_64
> Arch Linux.
>
> Compare the output of these two sed invocations:
> ```
> $ echo -e 'a\nb\n\0\nc\n' | sed -e '/\0/,$d'
> a
> b
>
> c
>
This works
$ echo -ne 'a\nb\n\0\nc\n' | sed -e '/\d000/,$d'
(\o000, \x00 also work). All documented here:
https://www.gnu.org/software/sed/manual/sed.html#Escapes
Whether sed maintainers want to also allow the \0 syntax, up to them of
course.
--
D.
Information forwarded
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bug-sed <at> gnu.org
:
bug#51462
; Package
sed
.
(Sat, 30 Oct 2021 07:12:01 GMT)
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Message #11 received at 51462 <at> debbugs.gnu.org (full text, mbox):
(Adding Eric Blake for POSIX opinion)
Hello,
On 2021-10-28 11:32 a.m., Davide Brini wrote:
> On Thu, 28 Oct 2021 15:25:42 +0000, Frances Wingerter <fw <at> immunant.com>
> wrote:
>>
>> Compare the output of these two sed invocations:
>> ```
>> $ echo -e 'a\nb\n\0\nc\n' | sed -e '/\0/,$d'
>>
> $ echo -ne 'a\nb\n\0\nc\n' | sed -e '/\d000/,$d'
>
> (\o000, \x00 also work). All documented here:
> https://www.gnu.org/software/sed/manual/sed.html#Escapes
>
> Whether sed maintainers want to also allow the \0 syntax, up to them of
> course.
Thanks Davide for the reply.
In GNU sed, "\0" in the replacement part acts identically to "&" -
referencing the whole matched portion.
This is the implemented behavior (though undocumented?) since GNU sed
version 3, released in December 1995 - so not likely to be changed.
For comparison, in BSDs "\0" acts as literal zero (ASCII 48).
Interestingly, POSIX defines a "BACKREF" as:
[...] The character string consisting of a <backslash> character
followed by a single-digit numeral, '1' to '9'.
( from:
https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap09.html#tag_09_05
)
And so one could argue that this is a GNU extension that should be
disabled when used with "sed --posix".
I think we should keep "\0" undocumented to prevent proliferation of
this non-standard behavior.
regards,
- assaf
This bug report was last modified 3 years and 7 days ago.
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