$ acme.sh --set-default-ca --server letsencrypt_test
 Changed default CA to: https://acme-staging-v02.api.letsencrypt.org/directory

# acme.sh --register-account -m yourname@example.com
[...... 2022] Registering account: https://api.buypass.com/acme/directory                                　  
[...... 2022] Registered                                                                               　 
[...... 2022] ACCOUNT_THUMBPRINT='-DxxxxxxxAAAAAAAABBBBBBBBBBBBBBbCCCCCCCC'