Iterate through folders and convert your audiobooks from aax to m4b with ffmpeg to have a local backup or push audiobooks to audiobookshelf.

.env.dist

ACTIVATION_KEY=xxxxxxxx

m4b.sh

#!/bin/bash

# 1. Get activation key with -> https://github.com/mkb79/audible-cli
# 2. Create .env with ACTIVATION_KEY=xxxxxxxx
# 3. Run with "bash m4b.sh"


# Folder strucutur should look like this
# Root -> Author -> Title -> *****.aax file

if [ -f .env ]; then
  source .env
else
  echo ".env file not found!"
  exit 1
fi


for author_dir in */; do
  if [ -d "$author_dir" ]; then
    for audiobook_dir in "$author_dir"*/; do
      if [ -d "$audiobook_dir" ]; then
        cd "$audiobook_dir" || continue
        if ls *.aax 1> /dev/null 2>&1; then
          ffmpeg -activation_bytes "$ACTIVATION_KEY" -i "$(ls *.aax | head -n 1)" -c copy -f segment -segment_time 3600 -reset_timestamps 1 part%d.m4b && rm "$(ls *.aax | head -n 1)"
        fi
        cd - || continue  # Go back to the previous directory
      fi
    done
  fi
done