VirtualBox Guest Additions automated web installer for CentOS 6/7

vboxguestinstaller.sh

#!/bin/bash -e
# Utility script to install latest VirtualBox Guest Additions for CentOS 6/7
# @author Alex Gotev
#

if [[ $EUID -ne 0 ]]; then
   echo "This script must be run as root" 1>&2
   exit 1
fi

VBOX_GUEST_INSTALLED=$(modprobe vboxguest 2>/dev/null; echo $?)

if [ "$VBOX_GUEST_INSTALLED" == "0" ]
then
    echo "VirtualBox Guest Additions already installed"
else
    echo "Installing latest VirtualBox Guest Additions..."
    yum -y install kernel-devel gcc* dkms bzip2

    GUEST_ADDITIONS_VERSION=$(curl -s http://download.virtualbox.org/virtualbox/LATEST.TXT)
    DOWNLOAD_URL="http://download.virtualbox.org/virtualbox/${GUEST_ADDITIONS_VERSION}/VBoxGuestAdditions_${GUEST_ADDITIONS_VERSION}.iso"
    curl -L -# -o /tmp/guestadditions.iso "${DOWNLOAD_URL}"  2>&1
    mkdir /tmp/isoinstall
    mount /tmp/guestadditions.iso /tmp/isoinstall
    cd /tmp/isoinstall
    ./VBoxLinuxAdditions.run 2>&1 || true
fi

To download & run it, open a terminal as root and execute:

curl -L https://gist.github.com/gotev/10ab85f2a40b8f62597e57b1dfea34ca/raw/5407c59e323781df30e379f0e6c260c0d2f7e302/vboxguestinstaller.sh | bash