Title says it all, the closed beta invite states
git clone https://github.com/letsencrypt/letsencrypt
cd letsencrypt
./letsencrypt-auto --agree-dev-preview --server \
https://acme-v01.api.letsencrypt.org/directory auth
when in the latest client, it should be
git clone https://github.com/letsencrypt/letsencrypt
cd letsencrypt
./letsencrypt-auto --agree-dev-preview --server \
https://acme-v01.api.letsencrypt.org/directory certonly