domain_name=subdomain.domain.com
email=username@domain.com

git clone https://github.com/letsencrypt/letsencrypt /opt/letsencrypt
/opt/letsencrypt
chmod 755 /opt/letsencrypt /opt/letsencrypt
/etc/letsencrypt/./certbot-auto
mkdir -p /etc/letsencrypt/configs
echo "" > /etc/letsencrypt/configs/$domain_name