I have a main .ly file for a book and individual .ily files for each lesson.
Each .ily file has \layout{} and \midi{} statements.
I can batch-compile the .ily's, such that each midi is saved with the
filename of the .ily file, suppressing the pdf output:
lilypond-dno-print-pages lesson*.ily
This produces midis lesson1.midi, lesson2.midi....etc.
However, I can't find a similar command to suppress midi output when I
compile the book:
>lilypond -dno-midi book.ly
When I compile the book, I get multiple book.midi, book-1.midi...etc,
which are not needed. Currently, I'm just deleting those .midi files
manually.
Is there such a optional command to suppress midi output?