這是一個bash函數，它會檢查您的所有伺服器，假設您正在使用DNS循環法 . 請注意，這需要GNU日期，并且不适用于Mac OS
function check_certs () {
if [ -z "$1" ]
then
echo "domain name missing"
exit 1
fi
name="$1"
shift
now_epoch=$( date +%s )
dig +noall +answer $name | while read _ _ _ _ ip;
do
echo -n "$ip:"
expiry_date=$( echo | openssl s_client -showcerts -servername $name -connect $ip:443 2>/dev/null | openssl x509 -inform pem -noout -enddate | cut -d "=" -f 2 )
echo -n " $expiry_date";
expiry_epoch=$( date -d "$expiry_date" +%s )
expiry_days="$(( ($expiry_epoch - $now_epoch) / (3600 * 24) ))"
echo " $expiry_days days"
done
}
輸出示例：
$ check_certs stackoverflow.com
151.101.1.69: Aug 14 12:00:00 2019 GMT 603 days
151.101.65.69: Aug 14 12:00:00 2019 GMT 603 days
151.101.129.69: Aug 14 12:00:00 2019 GMT 603 days
151.101.193.69: Aug 14 12:00:00 2019 GMT 603 days