```common lisp
(cl:in-package #:asdf-user)

(defsystem :clobber
  :components
  ((:file "packages")
   (:file "clobber" :depends-on ("packages"))
   (:file "demo" :depends-on ("clobber"))
   (:file "demo2" :depends-on ("clobber"))))
```

Use option :SERIAL T to simplify system definition.
user
```common lisp
(cl:in-package #:asdf-user)

(defsystem :clobber
  :serial t
  :components
  ((:file "packages")
   (:file "clobber")
   (:file "demo")
   (:file "demo2")))
```
assistant