sync music folders and convert while at it...

convert_music.sh

#!/usr/bin/env bash
set -e # exit script if control-c is used

main() {
  USAGE="Usage: $0 source_dir destination_dir ffmpegcommand"
  if [ $# != 3 ] ; then
    echo $USAGE
    exit 1;
  fi
  # Convert relative path to absolute. Also remove trailing slash
  SOURCE_DIR="$(cd "$(dirname "$1")"; pwd)/$(basename "$1")"
  SOURCE_DIR=$(dirname "$SOURCE_DIR/temp") # this fixes . and ./
  DESTINATION_DIR="$(cd "$(dirname "$2")"; pwd)/$(basename "$2")"
  DESTINATION_DIR=$(dirname "$DESTINATION_DIR/temp") # this fixes . and ./

  # sync files and convert to mp3 if they dont exist as mp3 in destination yet
  find "$SOURCE_DIR" \( -iname '*.flac' -or -iname '*.m4a' \) -type f -print | while read -r FILE
  do
    ORIG_DIR=$(dirname "$FILE")
    # Get basename and remove extension
    BASE=$(basename "$FILE") # get filename
    BASE=${BASE%.*} # remove extension from filename
    NEW_DIR=${ORIG_DIR/$SOURCE_DIR/$DESTINATION_DIR}
    mkdir -p "$NEW_DIR"
    NEW_FILE="$NEW_DIR/$BASE.mp3"
    if [ ! -f "$NEW_FILE" ]; then
      echo "Converting $FILE to $NEW_FILE"
      # </dev/null added so ffmpeg doesn&#39;t read input
      $3 -hide_banner -i "$FILE" -c:a libmp3lame -q:a 2 "$NEW_FILE" </dev/null # standard mp3
    fi
  done

  # delete files from destination if they they don't exist in source anymore
  find "$DESTINATION_DIR" -type f -print | while read -r DESTFILE
  do
    echo "destfile " $(basename $DESTFILE)
    DELETE=true;
    find "$SOURCE_DIR" -type f -print | while read -r SOURCEFILE
    do
      echo "    sourcefile "$(basename $SOURCEFILE)
      if [[ $(basename ${DESTFILE%.*}) == $(basename ${SOURCEFILE%.*}) ]]; then
        echo "    found matching source file, don't delete"
        DELETE=false
        break
      fi
    done
    if [[ DELETE == true ]]; then
      echo "    could not find a matching source file for $DESTFILE, deleting"
      rm $DESTFILE
    fi
  done

  echo "syncing directory structure of $SOURCE_DIR to $DESTINATION_DIR"
  # NOTE This deletes even non empty directories in destination if they don't exit in source anymore
  rsync -av --delete-excluded --force --ignore-existing --include='*/' --exclude='*' "$SOURCE_DIR/" $DESTINATION_DIR

  echo "syncing all files from $SOURCE_DIR to $DESTINATION_DIR except .flac and .m4a files"
  rsync -av --ignore-existing --exclude='*.flac' --exclude='*.m4a' "$SOURCE_DIR/" $DESTINATION_DIR

}

main "$@"