Auto update Python 2.x to 3.x

1, How to check the python version

import sys

if sys.version_info < (3.0)

    print ("python version is 2.x")

else:

    print ("python version is 3.x")

2, How to change the default python version

sudo rm /usr/bin/python

sudo ln -s /usr/bin/python3.5 /usr/bin/python

3, How to install python3.x package

sudo apt install python3-pip

sudo pip3 install package

4,Auto update python2.x to python3.x

http://python-future.org/futurize.html#forwards-conversion

http://python-future.org/automatic_conversion.html

4.1 Install future

sudo pip install future

4.2 execute cmd

futurize --stage1 -w **/*.py

futurize --stage2 -w **/*.py

or

futurize -w **/*.py

5, Changed lib

2.x	3.x
import ConfigParser	import configparser
import copy_reg	import copyreg
import Queue	import queue
import SocketServer	import socketserver
import HTMLParser	import html
import urllib2	import urllib