一. 利用sys.stdout将print行导向到你定义的日志文件中，例如：

import sys

make a copy of original stdout route

stdout_backup = sys.stdout

define the log file that receives your log info

log_file = open("message.log", "w")

redirect print output to log file

sys.stdout = log_file

print "Now all print info will be written to message.log"

any command line that you will execute

...

log_file.close()

restore the output to initial pattern

sys.stdout = stdout_backup

print "Now this will be presented on screen"