Enable Software Collections (SCL)

Software Collections, also known as SCL is a community project that allows you to build, install, and use multiple versions of software on the same system, without affecting system default packages. By enabling Software Collections you will gain access to the newer versions of programming languages and services which are not available in the core repositories.

CentOS 7 ships with Python 2.7.5 which is a critical part of the CentOS base system. SCL will allow you to install newer versions of python 3.x alongside the default python v2.7.5 so that system tools such as yum will continue to work properly.

In order to enable SCL we need to install the CentOS SCL release file. It is part of the CentOS extras repository and can be installed by running the following command: SCL : https://wiki.centos.org/zh/AdditionalResources/Repositories/SCL

sudo yum install centos-release-scl

Installing Python 3 on CentOS 7

Now that we have access to the SCL repository we can install any Python 3.x version we need. Currently, the following Python 3 collections are available:

• Python 3.3
• Python 3.4
• Python 3.5
• Python 3.6

In this tutorial we will install Python 3.6 which is the latest version available at the time of writing. To do so type the following command on your CentOS 7 terminal:

sudo yum install rh-python36

Using Python 3

After the package rh-python36 is installed, check the Python version by typing:

python --version

You will notice that Python 2.7 is the default Python version in your current shell.

To access Python 3.6 you need to launch a new shell instance using the Software Collection scl tool:

scl enable rh-python36 bash

What the command above does is calling the script /opt/rh/rh-python36/enable which changes the shell environment variables.

If you check the Python version again, you’ll notice that Python 3.6 is the default version in your current shell now.

It is important to point out that Python 3.6 is set as the default Python version only in this shell session. If you exit the session or open a new session from another terminal Python 2.7 will be the default Python version.

参考：

https://linuxize.com/post/how-to-install-python-3-on-centos-7/#installing-python-3-on-centos-7