Subject: Re: bug#30681: What characters are in [[:space:]]?
From: Jim Meyering <[email-masked]>
To: Paul Eggert <[email-masked]>
Cc: [email-masked], Peng Yu <[email-masked]>
Date: Fri, 2 Mar 2018 15:19:08 -0800
List-Id: <debbugs-submit.debbugs.gnu.org>

tags 30681 notabug
stop

On Fri, Mar 2, 2018 at 2:32 PM, Paul Eggert <[email-masked]> wrote:
> On 03/02/2018 09:23 AM, Peng Yu wrote:
>>
>> Where is this info documented for grep?
>
> It's not documented for grep because it's not part of grep. It's part of
> your locale.

You can check for yourself.
In every one of the 818 locales installed on a Fedora 27 system, I see
the same five bytes:

$ perl -e 'print pack ("C*", 0..255);'|grep -ao '[[:space:]]'|tr -d
'\n' |od -ac -An
  ht  vt  ff  cr  sp
  \t  \v  \f  \r