$ for i in *.mkv ; do
mkvpropedit "$i" --edit track:a2 --set language=eng; \
mkvmerge --identify "$i"
done
The file is being analyzed.
The changes are written to the file.
Done.
File 'myfile.mkv': container: Matroska
Track ID 0: video (MPEG-1/2)
Track ID 1: audio (AC-3)
Track ID 2: audio (AC-3)
Track ID 3: audio (AC-3)
Track ID 4: subtitles (VobSub)
Track ID 5: subtitles (VobSub)
Track ID 6: subtitles (VobSub)
Chapters: 3 entries
...
...
...