function checkUpdate() { lastUpdateFile=$HOME/.config/last-system-upgrade if [ ! -f "$lastUpdateFile" ]; then echo "this system hasn't ever been updated using system-upgrade.sh" echo "run system-upgrade.sh now" return fi lastUpdate=$(cat $lastUpdateFile) now=$(date "+%s") if [[ $(( $now - $lastUpdate > 604800 )) -ne "0" ]]; then echo "this system hasn't been updated for over a week" echo "run system-upgrade.sh asap" return fi } checkUpdate