convert folder to ABS compatible (linux)

#!/bin/bash

FFPROBE="/usr/bin/ffprobe"
ROOT="."

find "$ROOT" -type f -name "*.m4b" | while read -r file; do

    # Extract metadata
    AUTHOR=$($FFPROBE -v quiet -show_entries format_tags=composer -of default=nw=1:nk=1 "$file")
    SERIES=$($FFPROBE -v quiet -show_entries format_tags=SERIES -of default=nw=1:nk=1 "$file")
    TITLE=$($FFPROBE -v quiet -show_entries format_tags=album -of default=nw=1:nk=1 "$file")

    # Fallbacks
    [ -z "$AUTHOR" ] && AUTHOR="Unknown Author"

    # If SERIES tag missing, use original folder name
    if [ -z "$SERIES" ]; then
        SERIES="$(basename "$(dirname "$file")")"
    fi

    [ -z "$TITLE" ] && TITLE="$(basename "$file")"

    # Sanitize folder names (replace bad characters)
    sanitize() {
        echo "$1" | sed 's/[:]/ -/g'
    }

    AUTHOR=$(sanitize "$AUTHOR")
    SERIES=$(sanitize "$SERIES")
    TITLE=$(sanitize "$TITLE")

    DEST="$ROOT/$AUTHOR/$SERIES/$TITLE"

    mkdir -p "$DEST"

    echo "Moving:"
    echo "  $file"
    echo "→ $DEST/"

    mv "$file" "$DEST/"

done

echo "Done."