VirtualBox Mount Shared Folder
Similar to VMWare Fusion 10 Mount Shared Folder, the shared folder may not work in a guest machine.
The issue can be solved by using the following command:
sudo mount -t vboxsf shared ~/shared
if we want to mount the folder as other users, we can specify the user and group ids
sudo mount -t vboxsf -o uid=1000,gid=1000 shared ~/shared