bug#43789: 27.1; Dired cannot handle file which name contains linebreak

bug#43789: 27.1; Dired cannot handle file which name contains linebreak

[Zhu Zihao]

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Step to reproduce:


1. Use touch from coreutils or find-file in Emacs to create a file which name contains a linebreak. (e.g. "line\nbreak")
2. Visit it in dired, you cannot do anything with this file because the characters after "\n" was ignored by dired.

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bug#43789: 27.1; Dired cannot handle file which name contains linebreak

[Eli Zaretskii]

> Date: Sun, 4 Oct 2020 16:58:06 +0800 (CST)
> From: "Zhu Zihao" <all_but_last@163.com>
> 
> 1. Use touch from coreutils or find-file in Emacs to create a file which name contains a linebreak. (e.g.
> "line\nbreak")
> 2. Visit it in dired, you cannot do anything with this file because the characters after "\n" was ignored by
> dired.

You need to add -b to the 'ls' switches, and then it will work.  That
is:

  C-u C-x d
  b RET

The "b RET" part makes the switches passed to 'ls' be "-alb" instead
of the default "-al".

bug#43789: Re: bug#43789: 27.1; Dired cannot handle file which name contains linebreak

[Zhu Zihao]

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Thank you, what about make this a part of default ls switch?





















At 2020-10-04 17:36:58, "Eli Zaretskii" <eliz@gnu.org> wrote:
>> Date: Sun, 4 Oct 2020 16:58:06 +0800 (CST)
>> From: "Zhu Zihao" <all_but_last@163.com>
>> 
>> 1. Use touch from coreutils or find-file in Emacs to create a file which name contains a linebreak. (e.g.
>> "line\nbreak")
>> 2. Visit it in dired, you cannot do anything with this file because the characters after "\n" was ignored by
>> dired.
>
>You need to add -b to the 'ls' switches, and then it will work.  That
>is:
>
>  C-u C-x d
>  b RET
>
>The "b RET" part makes the switches passed to 'ls' be "-alb" instead
>of the default "-al".

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bug#43789: 27.1; Dired cannot handle file which name contains linebreak

[Eli Zaretskii]

> Date: Sun, 4 Oct 2020 17:49:17 +0800 (CST)
> From: "Zhu Zihao" <all_but_last@163.com>
> Cc: 43789@debbugs.gnu.org
> 
> Thank you, what about make this a part of default ls switch?

I think this would have unwanted effect on other control characters.
ISTR this was discussed in the past, but I cannot find that discussion
at the moment.

bug#43789: 27.1; Dired cannot handle file which name contains linebreak

[Lars Ingebrigtsen]

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Eli Zaretskii <eliz@gnu.org> writes:

> I think this would have unwanted effect on other control characters.
> ISTR this was discussed in the past, but I cannot find that discussion
> at the moment.

I experimented a bit with two files, one with a newline and one with a
C-b character:


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The latter works in dired by default, while the former doesn't.

Adding b to the switches gives me:


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The C-b file still works, and the one with newline also works.

Does anybody remember what the unwanted effect was?

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#43789: Re: bug#43789: 27.1; Dired cannot handle file which name contains linebreak

[Zhu Zihao]

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It generally follows the escape rule of string in Elisp I think.





















At 2020-10-05 15:39:54, "Lars Ingebrigtsen" <larsi@gnus.org> wrote:
>Eli Zaretskii <eliz@gnu.org> writes:
>
>> I think this would have unwanted effect on other control characters.
>> ISTR this was discussed in the past, but I cannot find that discussion
>> at the moment.
>
>I experimented a bit with two files, one with a newline and one with a
>C-b character:
>

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bug#43789: 27.1; Dired cannot handle file which name contains linebreak

[Andreas Schwab]

One downside is that -b isn't POSIX.

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510  2552 DF73 E780 A9DA AEC1
"And now for something completely different."

bug#43789: 27.1; Dired cannot handle file which name contains linebreak

[Eli Zaretskii]

> From: Andreas Schwab <schwab@linux-m68k.org>
> Cc: Eli Zaretskii <eliz@gnu.org>,  43789@debbugs.gnu.org,  Zhu Zihao
>  <all_but_last@163.com>
> Date: Mon, 05 Oct 2020 09:49:13 +0200
> 
> One downside is that -b isn't POSIX.

Right.

I'm also not sure everyone would like to see \002 instead of ^B.

bug#43789: Re: bug#43789: 27.1; Dired cannot handle file which name contains linebreak

[Zhu Zihao]

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If "\002" can be display like ^B, we can make "\n" display like ^J in dired.





















At 2020-10-05 16:10:59, "Eli Zaretskii" <eliz@gnu.org> wrote:
>> From: Andreas Schwab <schwab@linux-m68k.org>
>> Cc: Eli Zaretskii <eliz@gnu.org>,  43789@debbugs.gnu.org,  Zhu Zihao
>>  <all_but_last@163.com>
>> Date: Mon, 05 Oct 2020 09:49:13 +0200
>> 
>> One downside is that -b isn't POSIX.
>
>Right.
>
>I'm also not sure everyone would like to see \002 instead of ^B.

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bug#43789: 27.1; Dired cannot handle file which name contains linebreak

[Lars Ingebrigtsen]

Eli Zaretskii <eliz@gnu.org> writes:

>> One downside is that -b isn't POSIX.
>
> Right.

I thought I remembered seeing some code in dired to probe for whether a
switch was supported or not...  did I just dream that?

> I'm also not sure everyone would like to see \002 instead of ^B.

Both control characters and newlines are pretty rare occurrences in file
names, but I'd take \002 for ^B over a Dired that doesn't work with \n.
Functionality over prettiness, or something. 

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#43789: 27.1; Dired cannot handle file which name contains linebreak

[Michael Albinus]

"Zhu Zihao" <all_but_last@163.com> writes:

> Step to reproduce:
>
> 1. Use touch from coreutils or find-file in Emacs to create a file
> which name contains a linebreak. (e.g. "line\nbreak")
> 2. Visit it in dired, you cannot do anything with this file because
> the characters after "\n" was ignored by dired.

I recommend to avoid file names containing line breaks. Tramp, for
example, cannot handle them at all.

Best regards, Michael.

bug#43789: 27.1; Dired cannot handle file which name contains linebreak

[Eli Zaretskii]

> Date: Mon, 5 Oct 2020 16:18:11 +0800 (CST)
> From: "Zhu Zihao" <all_but_last@163.com>
> Cc: "Andreas Schwab" <schwab@linux-m68k.org>, larsi@gnus.org, 
> 	43789@debbugs.gnu.org
> 
> If "\002" can be display like ^B, we can make "\n" display like ^J in dired.

The display comes from 'ls'.

bug#43789: 27.1; Dired cannot handle file which name contains linebreak

[Eli Zaretskii]

> From: Michael Albinus <michael.albinus@gmx.de>
> Date: Mon, 05 Oct 2020 11:30:50 +0200
> Cc: 43789@debbugs.gnu.org
> 
> "Zhu Zihao" <all_but_last@163.com> writes:
> 
> > Step to reproduce:
> >
> > 1. Use touch from coreutils or find-file in Emacs to create a file
> > which name contains a linebreak. (e.g. "line\nbreak")
> > 2. Visit it in dired, you cannot do anything with this file because
> > the characters after "\n" was ignored by dired.
> 
> I recommend to avoid file names containing line breaks. Tramp, for
> example, cannot handle them at all.

Cannot agree more.  And I think we shouldn't tweak our implementation
too much for such use cases, given that there's an easy workaround.

bug#43789: 27.1; Dired cannot handle file which name contains linebreak

[Drew Adams]

> > 1. Use touch from coreutils or find-file in Emacs to create a file
> > which name contains a linebreak. (e.g. "line\nbreak")
> > 2. Visit it in dired, you cannot do anything with this file because
> > the characters after "\n" was ignored by dired.
> 
> I recommend to avoid file names containing line breaks. Tramp, for
> example, cannot handle them at all.

And it's likely to mess up font-locking and other
Dired features that expect a newline to indicate
the end of a Dired line.

Dired, and other line-oriented displays, are a bit
fragile in this respect.

bug#43789: 27.1; Dired cannot handle file which name contains linebreak

[Richard Stallman]

[[[ To any NSA and FBI agents reading my email: please consider    ]]]
[[[ whether defending the US Constitution against all enemies,     ]]]
[[[ foreign or domestic, requires you to follow Snowden's example. ]]]

  > I recommend to avoid file names containing line breaks.

I agree -- but what if you have one, perhaps made by mistake?
The natural way for an Emacs user to rename or delete it
is with Dired.  It would be nice for Dired to handle it
at least enough to do that.

-- 
Dr Richard Stallman
Chief GNUisance of the GNU Project (https://gnu.org)
Founder, Free Software Foundation (https://fsf.org)
Internet Hall-of-Famer (https://internethalloffame.org)

bug#43789: 27.1; Dired cannot handle file which name contains linebreak

[Michael Albinus]

Richard Stallman <rms@gnu.org> writes:

Hi Richard,

>   > I recommend to avoid file names containing line breaks.
>
> I agree -- but what if you have one, perhaps made by mistake?
> The natural way for an Emacs user to rename or delete it
> is with Dired.  It would be nice for Dired to handle it
> at least enough to do that.

But that's already possible. The user might set temporarily

(setq dired-actual-switches "-alb")

Best regards, Michael.

bug#43789: Re: bug#43789: 27.1; Dired cannot handle file which name contains linebreak

[Zhu Zihao]

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I think I get an acceptable solution. thank you  all!


We may close this issue now.






At 2020-10-05 17:51:00, "Eli Zaretskii" <eliz@gnu.org> wrote:
>> From: Michael Albinus <michael.albinus@gmx.de>
>> Date: Mon, 05 Oct 2020 11:30:50 +0200
>> Cc: 43789@debbugs.gnu.org
>> 
>> "Zhu Zihao" <all_but_last@163.com> writes:
>> 
>> > Step to reproduce:
>> >
>> > 1. Use touch from coreutils or find-file in Emacs to create a file
>> > which name contains a linebreak. (e.g. "line\nbreak")
>> > 2. Visit it in dired, you cannot do anything with this file because
>> > the characters after "\n" was ignored by dired.
>> 
>> I recommend to avoid file names containing line breaks. Tramp, for
>> example, cannot handle them at all.
>
>Cannot agree more.  And I think we shouldn't tweak our implementation
>too much for such use cases, given that there's an easy workaround.

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bug#43789: 27.1; Dired cannot handle file which name contains linebreak

[Eli Zaretskii]

> Date: Wed, 7 Oct 2020 00:11:35 +0800 (CST)
> From: "Zhu Zihao" <all_but_last@163.com>
> Cc: "Michael Albinus" <michael.albinus@gmx.de>, 43789@debbugs.gnu.org
> 
> I think I get an acceptable solution. thank you  all!
> 
> We may close this issue now.

Done, thanks.