On Ubuntu 18, I have mounted an external drive in
/mnt/hdd/ and then I have changed its permission with
sudo chmod 777 /mnt/hdd/. In this way, all users can write in this external HDD. However, in this way, if user A creates a folder, then user B can delete the folder created by user A. How can I avoid this? Ideally, every user should be able to write to
/mnt/hdd/, but only the user that creates its folder should be able to write/delete it.