HOWTO: Install GCC 9 @ CentOS 7

a) Update Yum repositories

yum update -y

b) Install SCL

yum install -y centos-release-scl

c) Install development toolset

yum install -y devtoolset-9

d) Activate GCC v9

source /opt/rh/devtoolset-9/enable

https://stackoverflow.com/questions/67090507/how-to-install-gcc-g-9-on-centos-7-docker-centos7