Re: man-pages input, how to forward esc seq to tty output dev

"G. Branden Robinson" <[email protected]> Sat, 15 Nov 2025 04:07:18 -0600

Newsgroups	gmane.comp.printing.groff.general
Message-ID	<20251115100718.5ixujstrjunntva6@illithid>

Hi Phi,

At 2025-11-15T08:49:09+0100, Phi Debian wrote:
> I got a tool producing man-pages, i.e page that will be displayed by
> man(1) on tty device UTF8 capable with SGR's (namely vt100 emulator)
> 
> In my generated man-page (that will feed groff...grotty) I'd like to
> be able to emit ledgit escape sequence (again when in tty mode) but I
> can't find a way to emit the exact color I need. (Or other attributes)
> 
> Is there any advise.
> 
> So far I tried
> Here is text in \*[red]red\*[], \*[green]green\*[], and \*[blue]blue\[].
> 
> But I never get it either with
> man -l foo.1
> groff -man -Tutf8 -c foo.1

Nothing defines strings named `red`, `green`, or `blue` by default.
You'll have to do so yourself, or use a different escape sequence to
access these color names, which are defined in a different name space.

The grotty(1) man page has an extensive example.

Examples
     The following groff document exercises several features for which
     output device support varies: (1) bold style; (2) italic
     (underline) style; (3) bold‐italic style; (4) character composition
     by overstriking (“coöperate”); (5) foreground color; (6) background
     color; and (7) horizontal and vertical line drawing.

            You might see \f[B]bold\f[] and \f[I]italic\f[].
            Some people see \f[BI]both at once\f[].
            If the output device does (not) co\z\[ad]operate,
            you might see \m[red]red\m[].
            Black on cyan can have a \M[cyan]\m[black]prominent\m[]\M[]
            \D'l 1i 0'\D'l 0 2i'\D'l 1i 0' look.
            .\" If in nroff mode, end page now.
            .if n .pl \n[nl]u

     Given the foregoing input, compare and contrast the output of the
     following.

            $ groff -T ascii file
            $ groff -T utf8 -P -i file
            $ groff -T utf8 -P -c file | ul

Notice the `\m` and `\M` escape sequences.

You might want to avoid going through man(1) if you're using colors;
I've read that some implementations deliberately introduce an SGR
stripper to the rendering pipeline.

Regards,
Branden

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