Letsencrypt certificate for www and non-www domain

I have generated SSL certificate like so:

sudo git clone https://github.com/letsencrypt/letsencrypt /opt/letsencrypt./letsencrypt-auto certonly --standalone

Then I was asked for email ... and a domain name. I entered example.com

I figured out that I could enter multiple domains to be included in one certificate using different approach. E.g.:

sudo -H ./letsencrypt-auto certonly --standalone -d example.com -d www.example.com

I wonder if I could have entered multiple domains when I was promoted for them in a dialog or now I need to regenerate using a different approach?

Do I need to remove previous letsencrypt installation before going new way?

UPDATE -> SOLVED

sudo ./certbot-auto certonly --standalone -d example.com -d www.example.com