Manage multiple GCC installations on Ubuntu machine

multiple gcc installation

#
# Commands are tested on Ubuntu 14.04 
#

# Issue following command to verify which GCC version is installed
gcc --version
 --- OR --- 
g++ --version

gcc (Ubuntu 4.8.5-4ubuntu8~14.04.2) 4.8.5
Copyright (C) 2015 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

# Install the GCC-7
sudo apt-get update -y && \
sudo add-apt-repository -y ppa:ubuntu-toolchain-r/test && \
sudo apt-get update -y && \
sudo apt-get install gcc-7 g++-7 -y

# Let's manage two versions
sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-4.8 10 --slave /usr/bin/g++ g++ /usr/bin/g++-4.8
sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-7 20 --slave /usr/bin/g++ g++ /usr/bin/g++-7

# Machine is configured for GCC-7 at this point, let's see
gcc --version
 --- OR --- 
g++ --version

gcc (Ubuntu 7.3.0-21ubuntu1~14.04) 7.3.0
Copyright (C) 2017 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

# To switch b/w different versions
sudo update-alternatives --config gcc

# To see available versions
sudo update-alternatives --list gcc

# To remove link
sudo update-alternatives --remove gcc /usr/bin/gcc-7