hi,
this a script that creates sub-domain & nginx server block for that automatically.

for example, you have an application that need separate server block & directory for each user/subscriber. if you have that script, you dont need to create server bocks for each users manually. it will automatically create a sub-domain, a root directory for that, a server block and symlink that server block to yours sites-enabled. just you need to run that script/ bash upon user registration.