title: redirect from one folder into another using nginx
body: <p>I am running any Nginx file server. I have 2 main folders i.e. folder-a and folder-b. If a user tries to land on /folder-a/abc and it's a 404, I should auto-redirect to another folder like /folder-b/abc. How do I set up such a rule in Nginx? My top folder names will always be hard-coded names like folder-a and folder-b.</p>