Hello,
** Fabrice Couvreur [2019-04-08 12:08:44 +0200]:

> Hi,
> I compile all my files with Emacs and standalone context. I would like to
> compare context lmtx.
> I added this in my .emacs file but it does not work.

Does Emacs prints error messages? How do you run the command in Emacs?
Do you use AUCTeX or not? What messages do you see in *Messages* buffer?

> #############################################################################
> (eval-after-load "context"
>   '(setq TeX-command-list
>        (cons '("ConTeXt"
> "PATH=/home/viserion/context/tex/texmf-linux-64/bin:$PATH context
> --purgeall %s"
>         TeX-run-command nil t :help "Run context (MarkIV)")
> TeX-command-list)
>        ("ConTeXt"
> "PATH=/home/viserion/data/context/tex/texmf-linux-64/bin:$PATH context
> --purgeall %s"
>         TeX-run-command t t :help "Run context (LMTX)") t)
> )
> #############################################################################
> 
> 
> For information about GNU Emacs and the GNU system, type C-h C-a.
> File mode specification error: (wrong-type-argument symbolp (ConTeXt
> PATH=/home/viserion/data/context/tex/texmf-linux-64/bin:$PATH context
> --purgeall %s TeX-run-command t t :help Run context (LMTX)))
> 
> Thank you.
> Fabrice

P.S. I didn't try lmtx yet, on my agenda.

P.P.S. It might be more useful to discuss this topic on AUCTeX mailing
list if you use AUCTeX.

---
WBR, Vladimir Lomov

-- 
Nothing recedes like success.
		-- Walter Winchell