Configure multiple GCC versions on ubuntu

configure_muliple_gcc.sh

#!/usr/bin/env bash

sudo add-apt-repository -y ppa:ubuntu-toolchain-r/test
sudo apt update

sudo update-alternatives --remove-all gcc
sudo update-alternatives --remove-all g++
sudo apt-get install -y gcc-4.8 g++-4.8 gcc-4.9 g++-4.9 gcc-5 g++-5 gcc-6 g++-6 gcc-7 g++-7

sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-4.8 10
sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-4.9 20
sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-5 30
sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-6 40
sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-7 50

sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-4.8 10
sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-4.9 20
sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-5 30
sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-6 40
sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-7 50

sudo update-alternatives --set cc /usr/bin/gcc
sudo update-alternatives --set c++ /usr/bin/g++

sudo update-alternatives --config gcc
sudo update-alternatives --config g++

Clean and clear. Thank you.

Not working on Ubuntu 19.10

Indeed, can't get gcc-5 nor g++-5 on Ubuntu 19.10
Trying to build ROS2 and from what I've seen it needs gcc/g++ 5

beautiful. Saved me a lot of hassle.

You could add as a comment the following to investigate existing state:

namei `which cc`
namei `which c++`

great.