This post is older than a year. Consider some information might not be accurate anymore.
Pay attention that your credentials are stored in the config. A better way is to use ssh keys.
Setup proxy server for HTTP and HTTPS
git config --global http.proxy http://user:passwd@proxy.cinhtau.net:8080
git config --global https.proxy https://user:passwd@proxy.cinhtau.net:8080
Remove proxy server for HTTP and HTTPS
git config --global --unset http.proxy
git config --global --unset https.proxy
