Adding Cesium to OSGeoLive

#!/bin/bash
#This script is being built by Balasubramaniam Natarajan (bala150985 At gmail dot com)
#The purpose of this script is to install Cesium on OSGeoLive

USER_NAME="user"
USER_HOME="/home/user"
cd $USER_HOME

wget -c http://cesiumjs.org/releases/Cesium-1.4.zip
mkdir /tmp/build_cesium
cp Cesium-1.4.zip /tmp/build_cesium/

#The next four lines will make sure unzip program is intalled
IsUnZipPresent=`/usr/bin/which unzip | /usr/bin/wc -l`
if [ $IsUnZipPresent -eq 0 ]; then
apt-get install unzip
fi

if [ -d /tmp/build_cesium/cesium ]; then
rm -rf /tmp/build_cesium/cesium
fi

mkdir /tmp/build_cesium/cesium
unzip /tmp/build_cesium/Cesium-1.4.zip -d /tmp/build_cesium/cesium/

if [ -d /var/www/html/cesium ]; then
rm -rf /var/www/html/cesium
fi

cp -rf /tmp/build_cesium/cesium /var/www/html/

chgrp www-data -R /var/www/html/cesium

firefox -new-window http://localhost/cesium/Apps/HelloWorld.html -new-tab http://localhost/cesium/ &