lilypond-book accepts --loglevel=WARN, but not --loglevel=WARNING. I think WARN is for lilypond, not lilypond-book (according to the documentation), so maybe just misdocumented?
Using 2.24.3 Thank you, C >> lilypond-book --loglevel=WARN book.lytex > lilypond-book: error: file not found: book.lytex >> lilypond-book --loglevel=WARNING book.lytex > > lilypond-book: error: Unknown or invalid loglevel 'WARNING' > lilypond-book (GNU LilyPond) 2.24.3 > lilypond-book: error: file not found: book.lytex > lilypond-book -l loglevel --loglevel=loglevel Set the output verbosity to loglevel. Possible values are NONE, ERROR, WARNING, PROGRESS (default), and DEBUG. If this option is not used and the environment variable LILYPOND_BOOK_LOGLEVEL is set, its value is used as the log level. lilypond -l, --loglevel=level Set the verbosity of the console output to level. Possible values are: NONE No output at all, not even error messages. ERROR Only error messages, no warnings or progress messages. WARN Warnings and error messages, no progress. BASIC_PROGRESS Basic progress messages (success), warnings and errors. PROGRESS All progress messages, warnings and errors. INFO Progress messages, warnings, errors and further execution information. This is the default. DEBUG
