This small script lists files that have significant changes done to them with the last Magento upgrade. Run this under the same user that did the update. It'll ignore files that are new or only have changes in the comment section (ie Copyright update). Use the upgrade git commit reference hash as your first argument. This script assumes your Mag…

magentoUpgradeCheck.sh

#!/bin/bash

if [ ! "$1" ]; then
    echo "No commit reference found! Please add the commit hash of your upgrade."
    exit
fi

function echocolor() { # $1 = string
    COLOR='\033[1;33m'
    NC='\033[0m'
    printf "${COLOR}$1${NC}\n"
}

git show --name-only $1 > /tmp/tmp_filenames_magento_upgrade.txt
tail -n +7 /tmp/tmp_filenames_magento_upgrade.txt > /tmp/tmp_filenames_magento_upgrade_without_header.txt

userWhoDidTheUpdate="$(whoami)"

while read p; do
  if [ -f $p ]; then
      linesChanged="$(git blame $p | grep $userWhoDidTheUpdate | wc -l | xargs)"
      numberOfCommits="$(git log --pretty=oneline $p | wc -l | xargs)"
      if [ $linesChanged != '1' ] && [ $numberOfCommits != '1' ]; then
          echocolor "Lines changed: $linesChanged, commits: $numberOfCommits \t\t $p"
          echo "$(git log --pretty=oneline $p)"
          echo " "
      fi
  fi
done </tmp/tmp_filenames_magento_upgrade_without_header.txt

Example output;

Extra trick; on line 25, add 'grep -v COMMITHASH1|COMMITHASH2' etc etc to the git log call to filter out known commits such as your previous upgrade commits or commits that contain SUPEE patches.