-# This is to catch 'close failed: [Errno 9] Bad file descriptor'
-# message from os.close() in Subprocess.die().
-sys.stderr = open("err.log", 'w')
+# This is to catch 'close failed: [Errno 9] Bad file descriptor' message
+# from os.close() in Subprocess.die() and errors from from the subprocess.
+sys.stderr = open("err.log", 'a')