How to install pip with Python 3 on CentOS?

The manual way

Install pip

To install pip, securely download get-pip.py

Then run the following (which may require administrator access):

python get-pip.py 

If setuptools is not already installed, get-pip.py will install setuptools for you.

As two version (python 2.7 & python 3.5) can be found on my machine, the CMD I need to run is 

pip3

Reference: https://stackoverflow.com/questions/6587507/how-to-install-pip-with-python-3