Debian/Ubuntu: Virtualbox Guest Additions without GUI

[paia]

Install dkms package:

sudo apt-get install dkms

In VirtualBox: menu Devices -> Insert Guest Additions CD Image.
Back in linux:

sudo apt-get update && sudo apt-get install build-essential dkms linux-headers-$(uname -r)
cd /mnt
sudo ./VBoxLinuxAdditions.run
sudo reboot