*参考地址：https://www.cnblogs.com/ech2o/p/11748464.html
1.下载目标python版本压缩包(我的目录是/download)
wget http://npm.taobao.org/mirrors/python/3.8.0/Python-3.8.0.tgz
2.解压压缩包到/usr/local/
tar -zxvf Python-3.8.0.tgz -C /usr/local/
３.编译与安装
3.1 切换到
cd /usr/local
3.2 创建文件夹mkdir python3
3.3 切换目录cd /usr/local/Python-3.8.0
3.4 生成makefile文件./configure --prefix=/usr/local/python3
3.5 编译make
3.6 安装make install
4.创建python3软链(建议直接去第5步)
4.1
ln -s /usr/local/python3/bin/python3 /usr/bin/python3
4.2ln -s /usr/local/python3/bin/pip3 /usr/bin/pip3
报错ln: failed to create symbolic link ‘/usr/bin/python3’: File exists
解决方法，覆盖之前：用命令ln -sf /usr/local/python3/bin/python3 /usr/bin/python3
ln -sf /usr/local/python3/bin/pip3 /usr/bin/pip3
5.覆盖现有python，启动python时指向python3.8
1.备份旧python与pip
mv /usr/bin/python /usr/bin/python2_old
mv /usr/bin/pip /usr/bin/pip2_old
2.修改软链接
ln -s /usr/local/python3/bin/python3 /usr/bin/python
ln -s /usr/local/python3/bin/pip3 /usr/bin/pip
6.收尾，安装之后yum不能使用
1.编辑
vim /usr/bin/yum将第一行#!/usr/bin/python换成#!/usr/bin/python2.7
2.编辑vim /usr/libexec/urlgrabber-ext-down将第一行#!/usr/bin/python换成#!/usr/bin/python2.7
