Shell script to loop through a CSV file containing a series of values to find and replace

inputdata.csv

iterativeFindReplace.sh

#!/bin/bash
# set -x
# CSV FILE MUST HAVE EMPTY LINE AT END AND NO ""


INPUT=inputdata.csv
# to exclude multiple directories, wrap with {}. Must be full path
EXCLUDEDIR=/Users/JohnDoe/Sites/dir\ with\ space/excludedDirectory
# to exclude multiple files, wrap with {}
EXCLUDEFILE=file.csv
SEARCHDIR=/Users/JohnDoe/Sites/dir\ with\ space/
OLDIFS=$IFS
IFS=','
[ ! -f $INPUT ] && { echo "$INPUT file not found"; exit 99; }
while read newId oldId
do
    #echo "newId: $newId"
    #echo "oldId: $oldId"
    
	grep -RIlZ --exclude-dir="$EXCLUDEDIR" --exclude "$EXCLUDEFILE" "$oldId" "$SEARCHDIR" | while read -r line ; do
        #echo "$line"
        sed -i "" "s/$oldId/$newId/g" """$line"""
    done
done < $INPUT
IFS=$OLDIFS