rsync to Astell&Kern AK70 over mtp

ak70.sh

#!/bin/bash

# Requirements: go-mtpfs, rsync, fuse2

MUSICDIR="/home/<USER>/Music/"
DEVICEMUSICDIR="/mnt/ak70/Internal storage/Music/"
MOUNTPOINT="/mnt/ak70/"

print_usage() {
    echo "Usage: $0 mount|umount|drysync|fullsync|hardsync|sync"
}

if [ "$#" -ne 1 ]; then
    print_usage
    exit 1
fi

if [ "$1" == "mount" ]; then
    sudo go-mtpfs "$MOUNTPOINT" &
    exit 0
elif [ "$1" == "umount" ]; then
    sudo fusermount -u "$MOUNTPOINT"
    exit 0
fi

# normalize directories so nothing funky happens if someone sets the variables weird
normalize_directory() {
    local dir="$1"
    if [ -z "$dir" ]; then    
        echo "Set the variables in the script."    
        exit 1    
    fi    

    echo "$dir" | sed 's:/*$::' | sed 's:$:/:'
}

MUSICDIR=$(normalize_directory "$MUSICDIR")
DEVICEMUSICDIR=$(normalize_directory "$DEVICEMUSICDIR")

if sudo [ ! -d "$MUSICDIR" ]; then
    echo "Music directory does not exist: $MUSICDIR"
    exit 1
fi

if sudo [ ! -d "$DEVICEMUSICDIR" ]; then
    echo "Mount point does not exist: $DEVICEMUSICDIR"
    exit 1
fi

if [ "$DEVICEMUSICDIR" == "/" ]; then                                                                                                                                                          
    echo "Sync target is the root directory. No."                             
    exit 1                                                                                                                                                                                     
fi   

if [ "$1" == "drysync" ]; then
    sudo rsync -rvl --size-only --progress --dry-run "$MUSICDIR" "$DEVICEMUSICDIR"
elif [ "$1" == "fullsync" ]; then
    # Sync everything, but no deletes.
    sudo rsync -av --progress "$MUSICDIR" "$DEVICEMUSICDIR"
elif [ "$1" == "hardsync" ]; then
    # Sync everything and delete files from the receiver if they're not on the sending end.
    sudo rsync -av --delete --progress --dry-run "$MUSICDIR" "$DEVICEMUSICDIR"
    read -p "The above is the output of a dry run. Files may be deleted from your device. Are you sure you want to do all that? [Y/n]" -n 1 -r
    echo
    if [[ $REPLY =~ ^[Yy]$ ]]; then
        sudo rsync -avz --delete --progress "$MUSICDIR" "$DEVICEMUSICDIR"
    fi
elif [ "$1" == "sync" ]; then
    # standard use case when adding new albums or correcting art or something.
    # --size-only skips a lot of files. rsync's standard checksum method
    # doesn't really work over mtp for some reason, so without --size-only it
    # ends up re-syncing a lot of stuff.
    sudo rsync -rvl --size-only --progress "$MUSICDIR" "$DEVICEMUSICDIR"
else
    print_usage
    exit 1
fi

exit 0