Note: help and version output are generated by a naïve script which tries a few variants of
<command> --help, <command> -h etc. to find the command's help and version info.
Sometimes it gets lucky, sometimes it doesn't; if the output below looks wrong, it probably is.
mkvmerge --version (return code: 0)
mkvmerge v15.0.0 ('Duel with the Devil') 64-bit
mkvmerge --help (return code: 0)
mkvmerge -o out [global options] [options1] <file1> [@option-file.json]