batch extract subtitles from mkv files

mkvextractTracks.sh

#!/bin/bash -e

# a script that extracts the subtitle file of every mkv movie file and saves it with the same name
# copy to the folder where the mkv files live and run "./mkvextractTracks.sh" in terminal
# options: [trackID]
# example: ./mkvextractTracks.sh 1
#
# info:
# mkvextract is used to extract the subtitles, so mkvtoolnix app (which contains the mkvextract binary) is used:
# https://mkvtoolnix.download/downloads.html
# please adjust below path to point to mkvextract or this script won't work

extractorPath='/Applications/MKVToolNix-9.0.1.app/Contents/MacOS/mkvextract'
defaultTrackID=2
# Ensure we're running in location of script.
cd "`dirname $0`"

if [ $# -gt 0 ]
then
	defaultTrackID=$1
fi

for f in *; do
  if [[ $f == *.mkv ]];
    then
        echo $f
        $extractorPath tracks "$f" $defaultTrackID:"${f//mkv/srt}"
  fi
done

echo "Complete"

@Bananaman Oh thanks. your script is very usefull.

@anhthoai install python 3.5 and mkvtoolnix then windows command: python mkvextract-allsubs file.mkv

# Requires:
#   Python >= 3.5
#   MKVToolNix:
#   - Linux: Install "mkvtoolnix" via your native package manager.
#   - Mac: Install Homebrew use it to install the following package:
#     https://formulae.brew.sh/formula/mkvtoolnix
#   - Windows: Install Chocolatey and use it to install the following package:
#     https://community.chocolatey.org/packages/mkvtoolnix
#     (IMPORTANT: You MUST reboot Windows for the changes to take effect!)
#
# Usage:
#   mkvextract-allsubs [one or more MKV files to extract from]

@Bananaman is it possible to directly shell script on Linux without Python, please?

Came here for a potential one-liner but was sadly disappointed that this was just a way to extract subtitles from a single file.

Bananaman's script was borked for some reason, so no love there too.

In the end, the solution using pure Bash was not that hard.

Here's a one-liner:

for F in *.mkv; do MKV=$(echo $F | sed -e "s/\.mkv$//"); SUBS=$(mkvmerge -i "$MKV.mkv" | grep "SubRip/SRT" | cut -d ' ' -f3 | tr -d ':'); for SUB in $SUBS; do mkvextract tracks "$F" $SUB:"${MKV}_$SUB.srt"; done; done

Or if you prefer a more elegant solution in the form of a script you just execute in a folder:
https://gist.github.com/fevangelou/48da813ac1d5d0d207ff0acab1c09df2

Enjoy :)

Very usefull. Thank you @fevangelou ;)