Fix UNIX cli error-handling

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

src/unix.lisp

@@ -36,21 +36,22 @@
 ;; nil → nil
 (defun main ()
   "Actual invocation of the program. This is what you should set as :toplevel."
-  (error-print
-   99 ""
-   (multiple-value-bind (opts free) (opts:get-opts)
-     (when-opt opts :help (help))
-     (let* ((input-stream (choose-input-stream (car free)))
-            (url-base     (or (getf opts :url-base) (getf opts :download-dir) "mirror/"))
-            (download-dir (or (getf opts :download-dir) url-base)))
-       (when (not input-stream)
-         (error-print 1 "No HTML file provided. See --help for more information."))
-       (format
-        't
-        (mirror-img:mirror-img
-         input-stream
-         download-dir
-         :url-dir url-base))))))
+  (handler-case
+      (multiple-value-bind (opts free) (opts:get-opts)
+        (when-opt opts :help (help))
+        (let* ((input-stream (choose-input-stream (car free)))
+               (url-base     (or (getf opts :url-base) (getf opts :download-dir) "mirror/"))
+               (download-dir (or (getf opts :download-dir) url-base)))
+          (when (not input-stream)
+            (error-print 1 "No HTML file provided. See --help for more information."))
+          (format
+           't
+           (mirror-img:mirror-img
+            input-stream
+            download-dir
+            :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))