python将控制台输出保存至文件的方法

# assume the log file is 'a.log'
# for python2
print  a.log, 'print something'
# for python3
print('print something', file=a.log)

import sys
f = open('a.log', 'a')
sys.stdout = f
sys.stderr = f # redirect std err, if necessary

python a_script.py 2>&1 | tee a.log

import sys
class Logger(object):
 def __init__(self, filename='default.log', stream=sys.stdout):
  self.terminal = stream
  self.log = open(filename, 'a')

 def write(self, message):
  self.terminal.write(message)
  self.log.write(message)

 def flush(self):
  pass

sys.stdout = Logger(a.log, sys.stdout)
sys.stderr = Logger(a.log_file, sys.stderr) # redirect std err, if necessary

# now it works
print 'print something'