Finding diffs between clean and modified versions of WordPress

We have an issue where our developers try to update the core WordPress files. I wanted to find a way to keep them honest. here is my script:

# get WordPress
cd ~/src/
rm -f ~/src/latest.tar.gz
rm -rf ~/src/wordpress/
wget -q http://wordpress.org/latest.tar.gz
tar -xzf latest.tar.gz
CURRENTVERSION=$(grep "wp_version =" ~/src/wordpress/wp-includes/version.php | cut -f 3 -d " " | sed "s/;//" | sed "s/'//g")
# find WordPress installs and compare
for installpath in $(find $SEARCHPATH -name wp-config.php)
	do
		BASEDIR=$(dirname $installpath)
		INSTALLEDVERSION=$(grep "wp_version =" $BASEDIR/wp-includes/version.php | cut -f 3 -d " " | sed "s/;//" | sed "s/'//g")
		if [ $CURRENTVERSION == $INSTALLEDVERSION ]; then
		echo "====Comparing $BASEDIR to Source====" 
		diff -rq --exclude="wp-content" ~/src/wordpress  $BASEDIR #| grep differ
		fi
done