1）最快方案：只看响应头 + 状态码
curl -s -o /dev/null -w "%{http_code}\n" -I https://example.com
忽略证书校验
curl -sk -o /dev/null -w "%{http_code}\n" -I https://localhost
带有超时时间
curl -sk --connect-timeout 5 --max-time 10 \
-o /dev/null -w "%{http_code}\n" -I https://localhost