diff --git a/Makefile b/Makefile
index 39a99d7..61ea62d 100644
--- a/Makefile
+++ b/Makefile
@@ -171,3 +171,5 @@ qemu-gdb: $K/kernel .gdbinit fs.img
 	@echo "*** Now run 'gdb' in another window." 1>&2
 	$(QEMU) $(QEMUOPTS) -S $(QEMUGDB)
 
+format:
+	find . -name "*.[ch]" | xargs clang-format -i