Audacity Command Line Batch Tempo Modification

Audacity doesn't have a (native) CLI !

However, you can do that with ffmpeg.

Install it with

sudo apt-get install ffmpeg

For example

ffmpeg -i ./input.mp3 -filter:a "atempo=1.3" -vn ./output.mp3

The 1.3 means 130% of tempo.

EDIT: A quick script to do this for a lot of files.

I would suggesting not overwriting the originals, but rather make new files in the directory faster

mkdir /home/user/your/music/directory/faster

use your favorite editor

nano quick_casts.sh

#!/bin/bash
cd /home/user/your/music/directory

for f in *.mp3
do echo $f
ffmpeg -i "$f" -filter:a "atempo=1.3" -vn "faster/$f" -y
done

Change it to your directories, of course. I've also added "-y" to always overwrite files of the same name that exist in the directory faster.

make it executable

chmod +x quick_casts.sh