centos7安装python3 并设置为默认

https://blog.youkuaiyun.com/misaka_s/article/details/89509859
安装python3

yum install epel-release

yum install python36 python36-devel

修改默认python

 mv /usr/bin/python /usr/bin/python.bak
 ln -s /usr/bin/python3.6 /usr/bin/python

由于yum是基于python2，所以还需修改相关文件

vim /usr/bin/yum
vim /usr/libexec/urlgrabber-ext-down
将文件 #!/usr/bin/python修改为#!/usr/bin/python2即可

安装pip

 wget https://bootstrap.pypa.io/get-pip.py
python get-pip.py