嗯？这事就怪了。
具体错误：
./VBoxLinuxAdditions.run Verifying archive integrity... All good. Uncompressing VirtualBox 6.0.12 Guest Additions for Linux........ VirtualBox Guest Additions installer Removing installed version 6.0.12 of VirtualBox Guest Additions... Copying additional installer modules ... Installing additional modules ... VirtualBox Guest Additions: Starting. VirtualBox Guest Additions: Building the VirtualBox Guest Additions kernel modules. This may take a while. VirtualBox Guest Additions: To build modules for other installed kernels, run VirtualBox Guest Additions: /sbin/rcvboxadd quicksetup <version> VirtualBox Guest Additions: or VirtualBox Guest Additions: /sbin/rcvboxadd quicksetup all VirtualBox Guest Additions: Kernel headers not found for target kernel 4.19.0-6-amd64. Please install them and execute /sbin/rcvboxadd setup VirtualBox Guest Additions: Running kernel modules will not be replaced until the system is restarted
安装依赖库
注意一句“Kernel headers not found for target kernel”，缺少东西？
apt install gcc make dkms apt install build-essential linux-headers-`uname -r`
（还有介绍使用yum的，是另外一种系统）。
重新安装增强功能
共享文件夹
再挂载共享：设置，共享文件夹，改名为shared_win
mkdir shared_linux
sudo mount -t vboxsf -o "uid=csdn,gid=csdn,dmode=0755,fmode=0755" shared_win ~/shared_linux
-o之后并无用处，只是显得更砖业一些。
