如何在Virtual Box上设置Host和VM之间的共享目录

安装Oracle Virtual Box后，需要设置Host和VM之间的共享目录，以便更快捷的在两者之间传递文件。


Major steps：
1. Install the Linux Guest Additions (Section 4.2.2.1)
the Guest Additions are designed to be installed inside a virtual machine after the guest operating system has been installed. 
They consist of device drivers and system applications that optimize the guest operating system for better performance and usability.


1.1. sudo apt-get install dkms # prepare your guest system for building external kernel modules, Ubuntu/Debian
1.2. Devices -> "Mount CD/DVD-ROM"   # Add virtual CD-ROM for VBoxGuestAdditions.iso, Section 4.2.1.1
1.3. sh ./VBoxLinuxAdditions.run # as root


2. Set up shared folder for VM: when VM is not running, VM's Setting dialog box.
3. mount the shared folder from inside a VM 
mount -t vboxsf [-o OPTIONS] sharedname mountpoint


Please refer to Virtual Box's UserManual，section 4 Guest Additions.