acme.sh
A pure Unix shell script implementing ACME client protocol
...Support SAN and wildcard certs. Simple, powerful and very easy to use. You only need 3 minutes to learn it. Bash, dash and sh compatible. Purely written in Shell with no dependencies on python. Just one script to issue, renew and install your certificates automatically. Does not require root/sudoer access. Docker ready. IPv6 ready. Cron job notifications for renewal or error etc. It's probably the easiest & smartest shell script to automatically issue & renew the free certificates. After the cert is generated, you probably want to install/copy the cert to your Apache/Nginx or other servers. ...