Le ven. 17 avr. 2026 à 19:10, Paul Eggert <[email protected]> a écrit :
>
> On 2026-04-17 09:31, Laurent Lyaudet wrote:
> > Any possibility to have the part of the POSIX documentation related to
> > this "allowing", please?
>
> POSIX 1003.1-2024 Base Definitions 9.1 "Regular Expression Definitions"
> "invalid"
>
> https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/V1_chap09.html#tag_09_01_07
>
> Since \s is not invalid, GNU grep can treat it as an extension.
Thanks.
Still not obvious for me.
I mean that "abc" is not invalid but it is required to match "abc" obviously.
Similarly "\s" could be required to match "\s" instead of spaces.
My current understanding is that '\' followed by another character is
valid as a possible extension,
since the literals "\x" may be matched with "\\x".
Is that the logic?
Are there other strings than '\' followed by another character that
can be used as extensions, please?
