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Subject: [bug#30053] [PATCH 1/3] Improve appearance of tabular output.
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From: Roel Janssen <roel@gnu.org>
In-reply-to: <CA+xn8YDjApPwzx_1kR2pTuwVAyajXO+n5KN27WCGNAF2eX+rDg@mail.gmail.com>
Date: Fri, 12 Jan 2018 14:28:30 +0100
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To: Steve Sprang <steve.sprang@gmail.com>
Cc: 30053@debbugs.gnu.org


Steve Sprang writes:

> Hi Ludovic,
>
> On Thu, Jan 11, 2018 at 1:32 PM, Ludovic Courtès <ludo@gnu.org> wrote:
>> Long time no see!  ;-)
>
> Yeah, it's been a while!
>
>> I have a disappointing explanation I’m afraid: the reason columns look
>> this way is because they are tab-separated, which in turn makes it easy
>> to filter with ‘cut’:
>>
>> --8<---------------cut here---------------start------------->8---
>> $ guix package -A | cut -f1 | head
>> 0ad
>> 0ad-data
>> 0xffff
>> 4store
>> 4ti2
>> a2ps
>> aalib
>> abbaye
>> abc
>> abcde
>> --8<---------------cut here---------------end--------------->8---
>
> I'm still inserting a tab between columns, so I believe 'cut' still
> works as expected in this case. Initially, I was separating columns
> with a few spaces, but that broke some of the tests that were relying
> on cut, so I switched back to tab.
>
>> An example from the manual (info "(guix) Invoking guix build"):
>>
>>      guix build --quiet --keep-going \
>>        `guix package -A | cut -f1,2 --output-delimiter=@`
>
> Argh, this use case fails because of the extra inserted whitespace.
>
>> The idea was to have this shell-scripting-friendly format, and to
>> provide fancier output in other commands, such as --search (which is in
>> fact script-friendly as well thanks to recutils).
>>
>> Silly? Awesome? Ugly? What do people think?  :-)
>
> Another potential drawback of this patch is that it tends to make
> output lines longer than before. This might make line-wrapping less
> pleasant when using smaller terminal windows/screens.
>
> -Steve

If we use GNU awk instead of cut, I think any whitespace will work:
  $ guix package -A | awk '{ print $1 "@" $2 }'

And then we can optimize the output reading experience for our users
instead of for the 'cut' program.

Kind regards,
Roel Janssen