pip install using proxy in a virtual environment

Meanwhile, I know the solution. pip needs the environment variable HTTP_PROXY and HTTPS_PROXY in capital letters, instead of http_proxy. So append below text pattern at the end of your your '~/.bashrc'

HTTP_PROXY=http://username:pass@proxyaddress:port
export HTTP_PROXY
HTTPS_PROXY=http://username:pass@proxyaddress:port
export HTTPS_PROXY

Then, run source ~/.bashrc Now you can install all python packages using pip in your Ubuntu VM with proxy login.