Mounting after installing VirtualBox Guest Additions
For example, you may have a directory on your host OS shared as common. Use the following command to mount it on your Linux guest into /media/vbox/common directory:
mount -t vboxsf common /media/vbox/common
Note that the filesystem type ends with "sf" not "fs" as it might be expected.
Shared folder on host system can be configured as "Auto-mount" forcing guest to mount it automatically. However, there can be problems with permissions for the mounted files. Instead, configure static mount configuration in /etc/fstab file specifying mount point and user/group which is supposed to own the files in shared folder:
common /home/username/common vboxsf defaults,uid=1000,gid=1000 0 0
The mount operation will be done automatically during booting. Alternatively, as details are already provided in /etc/fstab, simplified command with mount location can be used for manual operations:
mount /home/username/common umount /home/username/common
Note that the shared folder should be configured with "Make Permanent" option in order to keep the configuration between VirtualBox restarts.