ffprobe - Subtitles - Extract all subtitles

Start with getting mapping of subtitle indexes to languages:

mappings=`ffprobe -loglevel error -select_streams s -show_entries stream=index:stream_tags=language -of csv=p=0 "Movie-1080p.mkv"
echo ${mappings}

returns:

2,eng
3,eng
4,spa

Then, substitute ${idx} & ${lang} with mapping values, e.g.:

ffmpeg -nostdin -hide_banner -loglevel quiet -i "Movie-1080p.mkv" -map 0:"${idx}" "Movie-1080p_${lang}_${idx}.srt"

Using Bash

function subs() {
  movie="${1}"
  filename="${1%.*}"
  mappings=`ffprobe -loglevel error -select_streams s -show_entries stream=index:stream_tags=language -of csv=p=0 "${movie}"`
  OLDIFS=$IFS
  IFS=,
  ( while read idx lang
  do
    echo "Exctracting ${lang} subtitle #${idx} from ${movie}"
    ffmpeg -nostdin -hide_banner -loglevel quiet -i "${movie}" -map 0:"$idx" "${filename}_${lang}_${idx}.srt"
  done <<< "${mappings}" )
  IFS=$OLDIFS
}
 
subs "$1"

NOTE: Example of command:

bash subs.sh Movie-1080p.mkv