cd /usr/local/src
wget https://dl.eff.org/certbot-auto
chmod a+x certbot-auto
./certbot-auto --nginx（自動）

出現以下內容表示成功：

IMPORTANT NOTES:

• Congratulations! Your certificate and chain have been saved at:
  /etc/letsencrypt/live/c.pensukeji.com/fullchain.pem
  Your key file has been saved at:
  /etc/letsencrypt/live/c.pensukeji.com/privkey.pem
  
  Your cert will expire on 2018-10-16. To obtain a new or tweaked
  version of this certificate in the future, simply run certbot-auto
  again with the "certonly" option. To non-interactively renew all
  of your certificates, run "certbot-auto renew"
• Your account credentials have been saved in your Certbot
  
  configuration directory at /etc/letsencrypt. You should make a
  secure backup of this folder now. This configuration directory will
  also contain certificates and private keys obtained by Certbot so
  making regular backups of this folder is ideal.

• If you like Certbot, please consider supporting our work by:

  Donating to ISRG / Let‘s Encrypt: https://letsencrypt.org/donate
  Donating to EFF: https://eff.org/donate-le

./certbot-auto renew --dry-run（測試自動續訂）
./certbot-auto renew（執行自動續訂）
定時任務
為了做到自動化，我們要設置計劃任務定時檢查更新
編輯/etc/crontab增加一行規則
**12** root ./usr/local/src/certbot-auto renew
詳細過程，手動過程及各個版本的安裝方式可到以下官網自行查看
Certbot官網網址：https://certbot.eff.org/

使用 certbot 對網站免費加 https 協議