This script is designed to work on Ubuntu (works on WSL2 perfectly) and macOS, and can be adapted to work under any linux distribution.
If you want a local domain, let's say example.com, simply run the script.
./script.sh example.com
This will generate your certificate and key files under the ./certs directory in the following format...
Authority: example.com-CA.pem
Certificate: example.com-CERT.pem
Key: example.com.key
The script will also add it to your OS certificate list. This includes Ubuntu Linux, macOS and Windows if under WSL2.
Use Edge or Safari to test certificate. Firefox gives some trouble with CACHE and cert validation when re-created. Haven't tested this on Chrome.
In case of Firefox:
Go to: about:config
Set: security.enterprise_roots.enabled to true