Fix UNIX cli error-handling

… I made a silly, brainless mistake here. :P

src/unix.lisp

@@ -36,8 +36,7 @@
 ;; nil → nil
 (defun main ()
   "Actual invocation of the program. This is what you should set as :toplevel."
-  (error-print
-   99 ""
+  (handler-case
       (multiple-value-bind (opts free) (opts:get-opts)
         (when-opt opts :help (help))
         (let* ((input-stream (choose-input-stream (car free)))
@@ -50,7 +49,9 @@
            (mirror-img:mirror-img
             input-stream
             download-dir
-         :url-dir url-base))))))
+            :url-dir url-base))))
+    (error (c)
+      (error-print 99 nil c))))
 
 (opts:define-opts
   (:name :help
@@ -69,6 +70,10 @@
              (error (c)
                (error-print 11 "Could not access or create directory." c))))))
 
+
+
+;;; Output
+;;; ————————————————————————————————————————
 ;; number stream → nil
 (defun help (&optional (exit-code 0) (stream *standard-output*))
   "Prints help message and dies."
@@ -82,7 +87,7 @@
 ;; number string condition → nil
 (defun error-print (exit-code &optional message condition)
   "Print an error-message and exit."
-  (format *error-output* "~@[~A~%~]~@[~A~%~]" message condition)
+  (format *error-output* "~@[~A~%~]~@[Error: ~A~%~]" message condition)
   (unix-opts:exit exit-code))