Letsencrypt how to use --preferred-problems

Question

This command:

$ letsencrypt certonly --manual --preferred-challenges dns --email [e-mail] --domains test001.bar.com 

outputs:

 letsencrypt: error: unrecognized arguments: --preferred-challenges dns 

From the documentation here: https://certbot.eff.org/docs/using.html#certbot-command-line-options

I find:

  --preferred-challenges PREF_CHALLS A sorted, comma delimited list of the preferred challenge to use during authorization with the most preferred challenge listed first (Eg, "dns" or "tls- sni-01,http,dns"). Not all plugins support all challenges. See https://certbot.eff.org/docs/using.html#plugins for details. ACME Challenges are versioned, but if you pick "http" rather than "http-01", Certbot will select the latest version automatically. (default: []) 

Why am I getting this error?

Answer 1

I found the answer, although the site indicates that letsencrypt and certbot match. This does not seem to be the case.

 $ apt-get install letsencrypt $ apt-get install python-pip $ pip install --upgrade pip $ pip install certbot $ certbot certonly --manual --preferred-challenges dns --email [e-mail] --domains test001.bar.com 

Is there a trick