From 0c362d907ddd2f954c5f4845ec0a331bd0fd0c8d Mon Sep 17 00:00:00 2001
From: lilydjwg <lilydjwg@gmail.com>
Date: Sat, 18 Apr 2015 16:39:43 +0800
Subject: [PATCH] nvtake: backup oldver before overwriting

---
 nvchecker/tools.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/nvchecker/tools.py b/nvchecker/tools.py
index c385e8a..31fe87a 100644
--- a/nvchecker/tools.py
+++ b/nvchecker/tools.py
@@ -30,6 +30,10 @@ def take():
   for name in args.names:
     oldvers[name] = newvers[name]
 
+  try:
+      os.rename(s.oldver, s.oldver + '~')
+  except FileNotFoundError:
+      pass
   core.write_verfile(s.oldver, oldvers)
 
 def cmp():