CentOS默认安装的是Python2.7.x，对于需要Python3的场合，需要自行安装，这里给出在CentOS7.6上安装Python3的步骤。由于系统对默认的Python2.7.x有依赖，所以我们尽量不改变原有版本。

环境：CentOS7.6，默认Python2.7.5

1、安装依赖环境

sudo yum -y install zlib-devel bzip2-devel openssl-devel ncurses-devel sqlite-devel readline-devel tk-devel gdbm-devel db4-devel libpcap-devel xz-devel

2、下载python3

sudo wget https://www.python.org/ftp/python/3.6.2/Python-3.6.2.tgz

3、为python3创建安装目录

sudo mkdir /usr/local/python3

4、解压并切换到安装文件中

sudo tar -zxvf Python-3.6.2.tgz
sudo cd Python-3.6.2

5、配置并安装

sudo ./configure –prefix=/usr/local/python3
sudo make && make install

6、创建python3、pip3软连接

sudo ln -s /usr/local/python3/bin/python3 /usr/bin/python3
sudo ln -s /usr/local/python3/bin/pip /usr/bin/pip3

7、将python默认设置为python3

sudo ln -s /usr/local/python3/bin/python3 /usr/bin/python
sudo ln -s /usr/local/python3/bin/pip /usr/bin/pip
sudo vi /usr/bin/yum 将第一行的”#!/usr/bin/python” 改为 “#!/usr/bin/python2”
sudo vi /usr/libexec/urlgrabber-ext-down 将第一行的”#!/usr/bin/python” 改为 “#!/usr/bin/python2”
运行yum，不报错即配置完成。