diff --git a/nix/sync-with-upstream b/nix/sync-with-upstream
index 69bd1fbee7..1f11fd7d47 100755
--- a/nix/sync-with-upstream
+++ b/nix/sync-with-upstream
@@ -61,7 +61,8 @@ do
     fi
 done
 
-cp -v "$top_srcdir/nix-upstream/"{COPYING,AUTHORS} "$top_srcdir/nix"
+cp -v "$top_srcdir/nix-upstream/COPYING" "$top_srcdir/nix"
+cp -v "$top_srcdir/nix-upstream/AUTHORS" "$top_srcdir/nix"
 
 # Substitutions.
 sed -i "$top_srcdir/nix/libstore/gc.cc"					\