diff -r 9e61563edb67 Lib/formatter.py
--- a/Lib/formatter.py	Sun Aug 11 16:48:44 2013 -0700
+++ b/Lib/formatter.py	Mon Aug 12 16:14:03 2013 +0800
@@ -433,11 +433,15 @@
         fp = open(sys.argv[1])
     else:
         fp = sys.stdin
-    for line in fp:
-        if line == '\n':
-            f.end_paragraph(1)
-        else:
-            f.add_flowing_data(line)
+    try:
+        for line in fp:
+            if line == '\n':
+                f.end_paragraph(1)
+            else:
+                f.add_flowing_data(line)
+    finally:
+        if fp is not sys.stdin:
+            fp.close()
     f.end_paragraph(0)