Proceed as pi.
NTFS file system
sudo apt-get install ntfs-3g
Find location
sudo fdisk -l
result: /dev/sda1
Device Boot Start End Sectors Size Id Type
/dev/mmcblk0p1 8192 137215 129024 63M c W95 FAT32 (LBA)
/dev/mmcblk0p2 137216 126613503 126476288 60.3G 83 Linux
Disk /dev/sda: 931.5 GiB, 1000204885504 bytes, 1953525167 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x518c5f10
Device Boot Start End Sectors Size Id Type
/dev/sda1 2048 1953521663 1953519616 931.5G 7 HPFS/NTFS/exFAT
Create target directory
sudo mkdir -m 1777 /data
Mount USB-HDD
sudo mount -w -o uid=pi,gid=pi /dev/sda1 /data
ls
ls -lha /data
Unmount USB-HDD
sudo umount /dev/sda1