This script converts a plain text file, e.g. article.txt into a mp3 audiobook using the MacOS text-to-speech accessibility command-line tool `say`. Adjust the `VOICE` and `RATE` parameters to customize to your liking. Note this requires running on MacOS.

txt2mp3.sh

#!/usr/bin/env bash
set -e
# This script converts any text file into a mp3 audiobook using the MacOS
# text-to-speech accessibility command-line tool `say`.
# Adjust the `VOICE` and `RATE` parameters to customize to your liking:
VOICE="Alex"
RATE="295"  # pretty fast


if [ $# -eq 0 ]; then
    echo "Usage: $0 article.txt";
    exit 1
fi

txtfilename="$1"
aifffilename="$(basename -- "$txtfilename" .txt).aiff"
mp3filename="$(basename -- "$txtfilename" .txt).mp3"


echo "Convering $txtfilename to mp3..."

# 1. Speak the text file, saving as an .aiff audio file
say -v $VOICE -r $RATE -f "$txtfilename" -o "$aifffilename"

# 2. Convert the .aiff to .mp3
ffmpeg  -hide_banner -loglevel error \
  -i "$aifffilename" \
  -b:a 128k  "$mp3filename"

# 3. Remove the .aiff file
rm "$aifffilename"

echo "Done. Result saved to $PWD/$mp3filename"