If you do not want glissando lines on all notes in a chord in order you’ll need
to set a glissandoMap, like
\version "2.22.1"
\relative c'' {
\time 3/4
\slashedGrace {a8}
\once \set glissandoMap = #'((1 . 1))
<a fis'>2 \glissando <a a'>8 <a b'>16 <a a'> }
It is explained in a little more detail here:
https://lilypond.org/doc/v2.22/Documentation/notation/expressive-marks-as-lines
> 14 sep. 2021 kl. 22:31 skrev Carlos Martinez <car...@newsoundmusicstudio.com>:
>
> I need to show the glissando from the a to a not both notes? Can I take one
> of the glissandos off?
>
>
>
> Glissando
>
> \slashedGrace {a8} <a fis'>2 \glissando <a a'>8 <a b'>16 <a a'>
