diff --git a/gash/compat.scm b/gash/compat.scm
index 7d067bd..41c6544 100644
--- a/gash/compat.scm
+++ b/gash/compat.scm
@@ -250,8 +250,12 @@
 
   (define (open-file filename mode)
     (cond
-     ((string=? mode "r") (open-input-file filename))
-     ((string=? mode "w") (open-output-file filename))
+     ((or (string=? mode "r")
+          (string=? mode "rb"))
+      (open-input-file filename))
+     ((or (string=? mode "w")
+          (string=? mode "wb"))
+      (open-output-file filename))
      (else (error "Unsupported file mode" mode))))
 
   ;; Because Mes is not careful when resolving syntax, this will