Lego: [CLI] generate certbot like files

[mhf-ir]

How to use lego CLI to generate

• fullchain.pem
• cert.pem
• chain.pem
• privkey.pem

[dmke]

Executing lego run will look like this:

$ cd .../some/where
$ lego --domains example.com [some options omitted] run

This will create a directory .../some/where/.lego/certificates:

$ ls .lego/certificates
example.com.crt example.com.issuer.crt  example.com.json    example.com.key

where:

• $domain.crt is the server certificate (including the CA certificate; equivalent to fullchain.pem)
• $domain.key it the server certificates' private key and key (= privkey.pem),
• $domain.issuer.crt is only the CA certificate, and
• $domain.json contains some meta information.

Notes:

1. The path of the .lego directory can be changed by explicitly adding a --path flag (like lego --path /opt/lego/ ...).
2. All .crt and the .key file are PEM encoded (they're just text files), the file extension (usually) doesn't matter.

[dmke]

Notes to self:

• [x] improve https://go-acme.github.io/lego/usage/cli/ and state where to find the certificate files in a more obvious way
• maybe add a --fullchain flag to auto-generate the aforementioned full chain file

[dmke]

@mhf-ir: I'm sorry, I've misread the code. Lego actually already writes the full chain to $domain.crt. I've updated my answer above: you don't need to cat domain.issuer.crt domain.crt > domain.fullchain.crt.