python如何打印出日志文件

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"