[pjb@despina org.macports:0 ~]$ sbcl --noinform --non-interactive --no-userinit --eval '(require :asdf)' --load '/tmp/hello.asd' --eval '(asdf:oos (quote asdf:compile-op) "hello")'
; compiling file "/private/tmp/hello.lisp" (written 08 DEC 2018 01:10:27 AM):
; compiling (DEFPARAMETER HELLO ...)

; /Users/pjb/.cache/common-lisp/sbcl-1.4.9-macosx-x64/private/tmp/hello-tmpGHU3ALSV.fasl written
; compilation finished in 0:00:00.001
; compiling file "/private/tmp/main.lisp" (written 08 DEC 2018 01:17:21 AM):
; compiling (FORMAT T ...)
; compiling (FINISH-OUTPUT)

; /Users/pjb/.cache/common-lisp/sbcl-1.4.9-macosx-x64/private/tmp/main-tmpAAURSO1.fasl written
; compilation finished in 0:00:00.000
[pjb@despina org.macports:0 ~]$ sbcl --noinform --non-interactive --no-userinit --eval '(require :asdf)' --load '/tmp/hello.asd' --eval '(asdf:oos (quote asdf:load-op) "hello")'
Hello World!
[pjb@despina org.macports:0 ~]$ cat /tmp/hello.lisp
(defparameter hello "Hello World!")
[pjb@despina org.macports:0 ~]$ cat /tmp/main.lisp
(format t "~A~%" hello)
(finish-output)
[pjb@despina org.macports:0 ~]$ cat /tmp/hello.asd
(asdf:defsystem "hello"
  :description "Hello world."
  :author "Pascal J. Bourguignon"
  :version "1.2.0"
  :license "GPL3"
  :depends-on ( #|some common asdf systems may be provided, and loaded here |# )
  :components ((:file "hello")
               (:file "main" :depends-on ("hello")))
  #+asdf-unicode :encoding #+asdf-unicode :utf-8)
[pjb@despina org.macports:0 ~]$