Loops over files in a folder and checks if they changed. If they stay the same in 3 loops of 5s wait the script will end

file_size_check.sh

#!/bin/bash

folder=${1};
diff=1;
sleeptime=5;

if [ ! -d "${folder}" ]; then
    echo "Folder: ${folder} not found";
    exit;
fi;

declare -A file_sizes;

echo "[START CHECK]";
# get all files in this folder so we can stat them for size
for file in $(ls -1 ${folder}/); do
    file_sizes[${file}]=$(stat -c %s "${folder}/${file}");
done;
while [ ${diff} -eq 1 ]; do
    diff=0;
    echo -n "<$(date +"%F %T")>(";
    for i in $(seq 1 3); do
        echo -n "#";
        for file in $(ls -1 ${folder}/); do
            size=$(stat -c %s "${folder}/${file}");
            or_size=${file_sizes[${file}]};
            #echo "FS: "${file_sizes[${file}]}" = "${size};
            if [ ${or_size} -ne ${size} ]; then
                diff=1;
            fi;
            echo -n ${diff};
            file_sizes[${file}]=${size};
        done;
        # wait
        sleep ${sleeptime};
    done;
    echo ")";
done;

echo "";
echo "[DONE: Sizes have not changed in the last ${sleeptime} seconds in ${folder}]";