google
Usability: default for -d when already registered ?
Another nitpick on first playing with your program: once I got it to register, I immediately proceeded to register once more against the staging server, using acme reg -c .config/acme.staging -d letsencrypt-staging. That worked fine, and I can use acme whoami -c .config/acme.staging to look at the registration details.
Next, I tried acme cert -c .config/acme.staging -manual me.example.com (of course with my own domain). That got me an error: me.example.com: 403 urn:acme:error:unauthorized: No registration exists matching provided key
Not a big issue - I simply have to once more add the -d letsencrypt-staging option, and then it works fine!
However, seeing that the "staging" URI is known (with whoami, or looking at the config file) already when the -c option is given - shouldn't then -d default to that URI from the configuration, like it does with whoami?
I see you already got in type userConfig (and account.conf) a field CA - but it's not used anywhere.
Let's see whether I can make my first useful changes to a go program, and make a pull request... :-)
Sorry for the duplicate pull request, by git-fu is lacking...
I'll look at the code a bit further tomorrow, with an eye on other places that might profit from the saved directory URI