sudo yum -y update
sudo yum -y install bzip2 gcc kernel-devel

sudo mkdir /mnt/cdrom
sudo mount /dev/cdrom /mnt/cdrom

sudo /mnt/cdrom/VBoxLinuxAdditions.run
sudo umount /mnt/cdrom

sudo mkdir /mnt/share
sudo mount -t vboxsf sharename /mnt/share

sudo usermod -G vboxsf -a vbird1