GNU bug report logs - #33577
doc: mention find/stat in ls documentation

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

From: 積丹尼 Dan Jacobson <jidanni <at> jidanni.org>
To: bug-coreutils <at> gnu.org
Subject: ls lacks null terminator option
Date: Sun, 02 Dec 2018 18:53:06 +0800

For files with blanks in their names,
one shouldn't need this workaround:
$ ls -t | tr \\n \\0 | xargs -0 more > /tmp/z.txt
Please add a --print0 option. like find(1) has.

ls (GNU coreutils) 8.30

Message #8 received at 33577 <at> debbugs.gnu.org (full text, mbox):

From: Bob Proulx <bob <at> proulx.com>
To: 33577 <at> debbugs.gnu.org,
 積丹尼 Dan Jacobson <jidanni <at> jidanni.org>
Subject: Re: bug#33577: ls lacks null terminator option
Date: Mon, 3 Dec 2018 12:55:30 -0700

積丹尼 Dan Jacobson wrote:
> For files with blanks in their names,
> one shouldn't need this workaround:
> $ ls -t | tr \\n \\0 | xargs -0 more > /tmp/z.txt
> Please add a --print0 option. like find(1) has.

I think that adding a --print0 option to 'ls' is not wise because it
would suggest to people seeing it that 'ls' should be used in scripts.
But 'ls' is a command designed for human interaction not for use in
scripts.  Using 'find' for scripted use is the desired utility.

Such a patch has previously been submitted.

  http://lists.gnu.org/archive/html/coreutils/2014-02/msg00005.html

Bob

Message #11 received at 33577 <at> debbugs.gnu.org (full text, mbox):

From: 積丹尼 Dan Jacobson <jidanni <at> jidanni.org>
To: Bob Proulx <bob <at> proulx.com>
Cc: 33577 <at> debbugs.gnu.org
Subject: Re: bug#33577: ls lacks null terminator option
Date: Wed, 05 Dec 2018 04:35:09 +0800

Bob, I remember from my K&R Unix book that ls can be used in scripts.
In fact that is why
$ ls
acts different than
$ ls | cat

Plus there are lots of things ls can do that find cannot.

For instance sorting.

How are you going to do
$ ls -t
with find?

Message #14 received at 33577 <at> debbugs.gnu.org (full text, mbox):

From: 積丹尼 Dan Jacobson <jidanni <at> jidanni.org>
To: Bob Proulx <bob <at> proulx.com>
Cc: 33577 <at> debbugs.gnu.org
Subject: Re: bug#33577: ls lacks null terminator option
Date: Wed, 05 Dec 2018 05:11:02 +0800

(Probably The Unix Programming Environment by K & P.)

Message #17 received at 33577 <at> debbugs.gnu.org (full text, mbox):

From: 積丹尼 Dan Jacobson <jidanni <at> jidanni.org>
To: Bob Proulx <bob <at> proulx.com>
Cc: 33577 <at> debbugs.gnu.org
Subject: Re: bug#33577: ls lacks null terminator option
Date: Wed, 05 Dec 2018 05:12:01 +0800

Don't let that ls colors stuff fool you. It originally didn't have that.

Message #20 received at 33577 <at> debbugs.gnu.org (full text, mbox):

From: 積丹尼 Dan Jacobson <jidanni <at> jidanni.org>
To: Bob Proulx <bob <at> proulx.com>
Cc: 33577 <at> debbugs.gnu.org
Subject: Re: bug#33577: ls lacks null terminator option
Date: Wed, 05 Dec 2018 05:13:26 +0800

Are you saying you want to enhance find(1) to sort its output?

Message #23 received at 33577 <at> debbugs.gnu.org (full text, mbox):

From: Bernhard Voelker <mail <at> bernhard-voelker.de>
To: 積丹尼 Dan Jacobson <jidanni <at> jidanni.org>,
 Bob Proulx <bob <at> proulx.com>
Cc: 33577 <at> debbugs.gnu.org
Subject: Re: bug#33577: ls lacks null terminator option
Date: Wed, 5 Dec 2018 11:25:29 +0100

On 12/4/18 9:35 PM, 積丹尼 Dan Jacobson wrote:
> Bob, I remember from my K&R Unix book that ls can be used in scripts.
> In fact that is why
> $ ls
> acts different than
> $ ls | cat
> 
> Plus there are lots of things ls can do that find cannot.
> 
> For instance sorting.

You didn't mention sorting in your original post, but actually that's a
typical post-action which can be glued together the UNIX way via pipes,
using the decorate-process-undecorate pattern:

  $ find -printf '%T@:%p\0' | sort -znr | cut -zd: -f2- | $PRG

with e.g.
  PRG='head -zn1'
to get the newest file.

And yes, if you really want to cater for arbitrary file names with blanks,
newlines, and control character - short: everything apart from '/' and '\0',
or more malicious file names e.g. starting with '-' or '--' to fool scripts,
then it is quite complex by nature to get it right: think about what
you have to do in the consuming $PRG to perform the processing safely.

> Are you saying you want to enhance find(1) to sort its output?

No, because that what 'sort' is for.

Have a nice day,
Berny

Message #26 received at 33577 <at> debbugs.gnu.org (full text, mbox):

From: 積丹尼 Dan Jacobson <jidanni <at> jidanni.org>
To: Bernhard Voelker <mail <at> bernhard-voelker.de>
Cc: 33577 <at> debbugs.gnu.org, Bob Proulx <bob <at> proulx.com>
Subject: Re: bug#33577: ls lacks null terminator option
Date: Wed, 05 Dec 2018 19:39:09 +0800

Fine. Put a message on top of (info "(coreutils) ls invocation")
saying that your pipes are better.

Message #29 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Peter Edwards <peter.edwards <at> csiro.au>
To: <bug-coreutils <at> gnu.org>
Subject: bug#33577: ls lacks null terminator option
Date: Wed, 5 Dec 2018 19:50:53 +1100

The output from stat(1) can be controlled, and is therefore easier
to parse than ls's human-friendly output, IMO.

Regards - Peter

Message #32 received at 33577 <at> debbugs.gnu.org (full text, mbox):

From: Assaf Gordon <assafgordon <at> gmail.com>
To: 積丹尼 Dan Jacobson <jidanni <at> jidanni.org>,
 Bernhard Voelker <mail <at> bernhard-voelker.de>
Cc: 33577 <at> debbugs.gnu.org, Bob Proulx <bob <at> proulx.com>
Subject: Re: bug#33577: ls lacks null terminator option
Date: Thu, 13 Dec 2018 13:39:46 -0700

tags 33577 notabug
severity 33577 wishlist
retitle 33577 doc: mention find/stat in ls documentation
stop

Hello,

On 2018-12-05 4:39 a.m., 積丹尼 Dan Jacobson wrote:
> Fine. Put a message on top of (info "(coreutils) ls invocation")
> saying that your pipes are better.

Given the suggested solution from Bob and Bernhard,
I'm marking this as a wishlish (todo) item
to improve ls's documentation.

regards,
 - assaf

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