Renew standalone let's encrypt cert shell script

renew_cert.sh

#! /bin/bash

## Because this is a standalone letsencrypt cert
## We have to stop nginx before doing renewal
CERT_IS_VALID=$(/usr/bin/ssl-cert-check -c /etc/letsencrypt/live/mydomain.com/fullchain.pem)
VALID_STR="Valid"
if [[ "$CERT_IS_VALID" =~ "$VALID_STR" ]];
then
    echo "Cert is valid"
else
    echo "\n=== Cert is expired ===\n"
    systemctl stop nginx
    /usr/bin/certbot renew
    systemctl start nginx
fi