Ubuntu安装Python2+Python3

sudo apt-get install python2.7 python2.7-dev
sudo apt-get install python3

命令：

python    默认执行python2
python2  执行python2
python3  执行python3

---

参考：

http://www.cnblogs.com/luckyalan/p/6703590.html

https://www.zhihu.com/question/21653286