linux下安装python3
https://www.cnblogs.com/JahanGu/p/7452527.html
linux环境下默认python2.x版本保留不动。新增python3
注意:
1、不改动已有的配置,新增ln -s /usr/local/python3/bin/python3 /usr/bin/python3和
ln -s /usr/local/python3/bin/pip3 /usr/bin/pip3
2、安装第三方插件: pip3 install flask