Extend certificate by one altname

Help
1

Is there something like this command?

certbot extend -domain maindomain -new newaltname

I created some certificate with

certbot certonly -d maindomain -d somealtname -d someotheraltname

and now want to get a certificate as if i would have requested it with

certbot certonly -d maindomain -d somealtname -d someotheraltname -d newaltname

but without remembering the old commandline to avoid mistakes like removing some other altname.

2

Unfortunately, something like that is not available yet. The recommended method for adding a new domain to an existing certificate is indeed to re-use the original command line, add the new domain with another -d flag, and add --expand to tell certbot not to create a new lineage (that would result in a new subdirectory in /etc/letsencrypt/live).