diff --git a/dump_msg.py b/dump_msg.py
index 665cda9..57e1d5b 100755
--- a/dump_msg.py
+++ b/dump_msg.py
@@ -1,11 +1,10 @@
 #!/usr/bin/env python2
 # -*- coding: UTF-8 -*-
 # File: dump_msg.py
-# Date: Fri Nov 21 14:36:23 2014 +0800
+# Date: Sat Nov 22 22:32:23 2014 +0800
 # Author: Yuxin Wu <ppwwyyxxc@gmail.com>
 
-from lib.Parser import WeChatDBParser
-
+from lib.parser import WeChatDBParser
 import sys, os
 
 if len(sys.argv) != 3:
diff --git a/lib/Msg.py b/lib/msg.py
similarity index 100%
rename from lib/Msg.py
rename to lib/msg.py
diff --git a/lib/Parser.py b/lib/parser.py
similarity index 95%
rename from lib/Parser.py
rename to lib/parser.py
index 8700aa0..3cee4b7 100644
--- a/lib/Parser.py
+++ b/lib/parser.py
@@ -1,14 +1,14 @@
 #!/usr/bin/env python2
 # -*- coding: UTF-8 -*-
-# File: Parser.py
-# Date: Sat Nov 22 22:17:27 2014 +0800
+# File: parser.py
+# Date: Sat Nov 22 22:32:05 2014 +0800
 # Author: Yuxin Wu <ppwwyyxxc@gmail.com>
 
 import sqlite3
 from collections import defaultdict
 import itertools
 
-from .Msg import WeChatMsg
+from .msg import WeChatMsg
 from .utils import ensure_unicode
 
 """ tables in concern:
diff --git a/lib/Render.py b/lib/render.py
similarity index 100%
rename from lib/Render.py
rename to lib/render.py
diff --git a/lib/Res.py b/lib/res.py
similarity index 100%
rename from lib/Res.py
rename to lib/res.py
diff --git a/plot_num_msg_by_time.py b/plot_num_msg_by_time.py
index 0ac265a..490d28f 100755
--- a/plot_num_msg_by_time.py
+++ b/plot_num_msg_by_time.py
@@ -1,10 +1,10 @@
 #!/usr/bin/env python2
 # -*- coding: UTF-8 -*-
 # File: plot_num_msg_by_time.py
-# Date: Fri Nov 21 15:57:40 2014 +0800
+# Date: Sat Nov 22 22:32:50 2014 +0800
 # Author: Yuxin Wu <ppwwyyxxc@gmail.com>
 
-from lib.Parser import WeChatDBParser
+from lib.parser import WeChatDBParser
 from lib.utils import ensure_unicode
 
 from datetime import timedelta, datetime
@@ -38,7 +38,6 @@ plt.show()
 
 # statistics by hour
 # I'm in a different time zone in this period:
-
 #TZ_DELTA = {(datetime(2014, 7, 13), datetime(2014, 10, 1)): -15}
 #def real_hour(x):
     #for k, v in TZ_DELTA.iteritems():