Subject: Re: bug#63819: Gnu `grep '.*'` does not match an empty string.

From: Paul Eggert <[email-masked]>
Date: Wed, 31 May 2023 17:42:47 -0700

On 2023-05-31 10:18, Bob Vincent Il (US) via Bug reports for GNU grep wrote:
> I discovered only today that the following commands all behave identically:
> 
>    *   grep -q '.*'
>    *   grep -q '.\+'
>    *   grep -q .
>    *   grep -qE '.*'
>    *   grep -qE '.+'
>    *   grep -qE .

No they don't. For example:

$ echo '' | grep -q . ; echo $?
1
$ echo '' | grep -q '.*' ; echo $?
0