patch creation with diff from files where a copy of the file with the extension ".old" exists, there is a patch file per found file

create-patch.sh

#/bin/bash
#set -x
APP_NAME=$(basename -- "$0")
if [ -z "$1" ]; then
   echo -e "\n$APP_NAME [base dir (Default:.)] [base search dir (Default:".")] [search glob (Default:**/*.php.old)] [patches dir (Default:patches]"
   echo -e "\tThe base search and patches dir are relative to basedir!"
   echo -e "\tExpample: $APP_NAME:  wordpress web/wp patches"
   exit
fi

BASE_START="$(pwd)"
BASE_DIR="${BASE_START}"
[ ! -z "$1" ] && [ "." != "$1" ] && BASE_DIR="${BASE_DIR}/$1"
BASE_SEARCH_PATH=""
BASE_SEARCH_DIR="${BASE_DIR}"
[ ! -z "$2" ] && [ "." != "$2" ] && BASE_SEARCH_DIR="${BASE_SEARCH_DIR}/$2"
[ ! -z "$2" ] && [ "." != "$2" ] && BASE_SEARCH_PATH="$2/"
BASE_SEARCH_GLOB=${3:-"**/*.php.old"}
BASE_PATCH_DIR="${BASE_DIR}/${4:-"patches"}"

ERROR="FALSE"
if [ ! -d "${BASE_DIR}" ]; then
   echo "Base directory ""${BASE_DIR}"" not found!"
   ERROR="TRUE"
fi
if [ ! -d "${BASE_SEARCH_DIR}" ]; then
   echo "Search directory ""${BASE_DIR}"" not found!"
   ERROR="TRUE"
fi
if [ ! -d "${BASE_PATCH_DIR}" ]; then
   echo "Patches directory ""${BASE_PATCH_DIR}"" not found!"
   ERROR="TRUE"
fi
[ "$ERROR" = "TRUE" ] && exit

cd "${BASE_SEARCH_DIR}"
trap "cd ${BASE_START}" EXIT
shopt -s globstar
for fullfile in $BASE_SEARCH_GLOB; do # Whitespace-safe and recursive
    # echo "fullfile:$fullfile"
    fileName=$(basename -- "$fullfile")
    fileDir=$(dirname -- "$fullfile")
    origFileName="${fileName%.*}"
    if [ -f "${BASE_SEARCH_DIR}/${fileDir}/${origFileName}" ]; then
        patchFileName="${BASE_SEARCH_PATH}${fileDir}/${origFileName}"
        patchFileNameFixed="${BASE_PATCH_DIR}/${patchFileName//[^a-zA-Z0-9]/-}.patch"
        #echo "FF:${fullfile} - FN:${fullfile} - PN:${patchFileNameFixed}"
        echo "${fileDir}/${origFileName}"
        cd "${BASE_DIR}"
        diff -Naur "${BASE_SEARCH_PATH}${fileDir}/${fileName}" "${BASE_SEARCH_PATH}${fileDir}/${origFileName}"  > "${patchFileNameFixed}"
        cd "${BASE_SEARCH_DIR}"
    else
        echo "Error: Original file \"${fileDir}/${origFileName}\" not found!"
    fi
done