I have 33 audio files, each about 11 seconds long, and I'd like to merge them into one lossless file. How can I do this efficiently (i.e. without cut-pasting in Audacity 33 times)?

5 Answers 5


You can do this with ffmpeg and sox:

for i in *.mp3 *.ogg *.flac
  ffmpeg -i "$i" "$i.wav"

sox *.wav combined.wav
  • This worked perfectly! Thank you for the help.
    – ashastral
    Aug 1, 2010 at 0:11
  • sox doesn't work for OGG: /usr/local/Cellar/sox/14.4.2_1/bin/sox FAIL formats: no handler for detected file type 'opus'
    – The Onin
    May 7, 2018 at 22:18

Assuming you want to merge them alphabetically, by filename:

for f in ./*.{ogg,flac,mp3}; do echo "file '$f'" >> inputs.txt; done
ffmpeg -f concat -i inputs.txt output.wav

The for loop puts all the filenames in a file called inputs.txt, one-per-line, and the second one uses ffmpeg's concat demuxer to merge the files. It is possible to use printf instead of the loop like so:

printf "file '%s'\n" ./*.{ogg,flac,mp3} > inputs.txt

Assuming a modern shell, you can also use command substitution to do the whole thing in a single line.

ffmpeg -f concat -i <(printf "file '%s'\n" ./*.{ogg,flac,mp3}) output.wav
  • 1
    I believe this is the 'correct' ffmepg answer as it will not re-encode anything. Aug 28, 2013 at 0:59
  • Does not work if a file name contains ' Nov 11, 2014 at 6:21
  • ^ I'm talking about 1st command, didn't try other two yet. Nov 11, 2014 at 8:27
  • 1
    I get an error when I attempt the one-liner, but this works for me: ffmpeg -f concat -safe 0 -i <(for f in ./*.flac; do echo "file '$PWD/$f'"; done) output.flac
    – Peter
    Apr 10, 2020 at 22:02

If you start with only lossless files, you can use use shntool:

shntool join *.flac
  • I get this error: shntool [join]: warning: unsupported format 0xfffe (Unknown) while processing file: [file1.flac]
    – bonh
    Sep 14, 2019 at 4:06

It seems that the Sound Juicer that comes with Ubuntu writes broken FLAC files, which result in no MD5 signature in the file. MAKE A COPY of the directory containing the files you want to concatenate, then run the script below.
echo fixing broken FLAC files
find . -type f|grep .flac$ |while read file
flac -f --decode "$file" -o temp.wav
flac -f -8 temp.wav -o "$file"
rm temp.wav

Then run
shntool join *.flac
as above.


However, be aware that the shntool join will insist on joining them in collating sequence (alphabetical) order EVEN IF you specify them otherwise.

shntool join fileB.flac fileA.flac

will put A before B.

You can either rename the files first or use the -r parameter ("-r ask" will prompt for the order).

Frankly I find this irritating...

Also you can force the output mode, so if you're joining FLACs:

shntool join *.flac -o flac

will result in joined.flac rather than joined.wav

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.