diff --git a/update_tree.sh b/update_tree.sh
new file mode 100755
index 0000000..5861976
--- /dev/null
+++ b/update_tree.sh
@@ -0,0 +1,4 @@
+#!/bin/bash
+rsync -r --delete ../mame/3rdparty/{expat,libflac,lzma,nanosvg,utf8proc,zlib} 3rdparty/
+rsync -r --delete ../mame/src/{emu,frontend,lib,tools} src/
+rsync -r --delete --exclude="modules/lib/osd_getenv.cpp" ../mame/src/osd src/