#!/usr/bin/env bash

# Get yum transaction
yum --assumeno update > /root/yum-check.txt
grep -q yumtx /root/yum-check.txt || exit 0
cp $(tail -1 /root/yum-check.txt | awk '{print $NF}') /root/yum-transaction.yumtx

# Use yum output to construct a notification
echo "Updates available on $(date):" > /root/yum-notice.txt
grep -E '(base|updates).*[kM]' /root/yum-check.txt | awk '{print $1"-"$3}' >> /root/yum-notice.txt
echo -e "\n\nTo install these updates, run the following command:" >> /root/yum-notice.txt
echo "yum -y load-transaction /root/yum-transaction.yumtx" >> /root/yum-notice.txt

cat /root/yum-notice.txt | mailx -s "Update report from $(hostname)" -- you@acme.local