Manage multiple Python installations on Ubuntu machine

multiple python installation

#
# Commands are tested on Ubuntu 14.04 
#

# Install the python3 as Ubuntu 14.04 comes with Python2
sudo apt-get update -y && \
sudo apt-get install python-pip python3 python3-pip

# Let's manage two versions

# Ubuntu is already having pip2 as /usr/bin/pip. We need to remove it otherwise update-alternatives can't create symlinks
sudo rm /usr/bin/pip

sudo update-alternatives --install /usr/bin/python python /usr/bin/python2.7 10 --slave /usr/bin/pip pip /usr/bin/pip2
sudo update-alternatives --install /usr/bin/python python /usr/bin/python3.5 20 --slave /usr/bin/pip pip /usr/bin/pip3.5

# Machine is configured for python3 at this point, let's see
python --version
 --- OR --- 
pip --version

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

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

# To remove link
sudo update-alternatives --remove gcc /usr/bin/python3.5