Re: grep counting matches only with --color argument

[Juri Linkov]

Hi Tomas,

> why does this command shows the number of matches in the mode-line
>
>    (grep "grep -r --color -nH -e TODO ~/git/emacs-pdf")
>
> but this one (without --color argument) always shows 0?
>
>    (grep "grep -r -nH -e TODO ~/git/emacs-pdf")
>
> Is there a deeper reason that --color is required to see the number of
> matches?  Could it simply count the number of matched lines if no
> --color was specified?  Or is it not easy to detect?

Not easy to detect, indeed.  Emacs regexp functions can't be used
to find Grep input regexps in the Grep output.

> I would like to see the number of matches with alternative programs like
> ripgrep:
>
>    (grep "rg -nH --no-heading --color=always -e TODO ~/git/emacs-pdf")
>    (grep "rg -nH --no-heading --color=ansi -e TODO ~/git/emacs-pdf")
>
> But the --color argument here does not seem to have an effect.

grep.el in Emacs 28 was fixed 2-3 months ago to support ripgrep matches.