Centos7 VirtualBox Guest Additions installation

VMBox Centos 7 prepare for install VirtualBox Guest Additions [prepare.sh]

#!/bin/bash 

# ------------------------------------------------------------
# Centos7 VirtualBox Guest Additions installation
# Update kernel headers and install requirements for it
#
# USAGE sudo prepare.sh
#
# sudo requires for installation, export KERNEL_DIR and reboot
# ------------------------------------------------------------

## Requie run as sudo ##
if [[ $UID != 0 ]]; then
    echo "Please run this script with sudo:"
    echo "sudo $0 $*"
    exit 1
fi

## CentOS/RHEL 7/6/5 ##
yum update -y kernel*

## Install following packages ##
rpm -Uvh https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
yum install -y gcc kernel-devel kernel-headers dkms make bzip2 perl

## Add KERN_DIR environment variable ##
export KERN_DIR=/usr/src/kernels/$(uname -r)

## Mount VirtualBoxGuestAdditions ##
mkdir /media/VirtualBoxGuestAdditions
mount -r /dev/cdrom /media/VirtualBoxGuestAdditions

## Run installation ##
cd /media/VirtualBoxGuestAdditions
./VBoxLinuxAdditions.run

## Reboot after install ##
while true; do
    read -p "Do you wish to reboot now(it's necessary)?" yn
    case $yn in
        [Yy]* ) reboot; break;;
        [Nn]* ) exit;;
        * ) echo "Please answer yes or no.";;
    esac
done