mkvmerge

Merge and extract multimedia streams. More information: https://mkvtoolnix.download/doc/mkvmerge.html.

• Display information about a Matroska file:
  mkvmerge --identify {{path/to/file.mkv}}
• Extract the audio from track 1 of a specific file:
  mkvextract tracks {{path/to/file.mkv}} {{1}}:{{path/to/output.webm}}
• Extract the subtitle from track 3 of a specific file:
  mkvextract tracks {{path/to/file.mkv}} {{3}}:{{path/to/subs.srt}}
• Add a subtitle track to a file:
  mkvmerge --output {{path/to/output.mkv}} {{path/to/file.mkv}} {{path/to/subs.srt}}