Re: grep: RE error in ^*** ADVICE-ON-FAILURE-: repetition-operator operand invalid

[Eli Zaretskii]

> Date: Sat, 19 Nov 2022 11:49:26 +0000
> From: Gregory Heytings <gregory@heytings.org>
> cc: Po Lu <luangruo@yahoo.com>, emacs-devel@gnu.org
> 
> 
> >> That seems like a problem with Sun grep, isn't it?
> >
> > No, it's a problem with the regexp
> >
> 
> I'm not sure, how comes that GNU grep does not complain and does the right 
> thing, even with POSIXLY_CORRECT?

That's a feature in GNU Grep: it has extensions over the basic REs.