Опять же, не претендует на оригинальность, просто заметка
Terminal Proxy
If you want to configure proxy for apt-get,aptitude,wget use the following procedure
First you need to edit /etc/bash.bashrc file
gksudo gedit /etc/bash.bashrc
Add your proxy server details in the following format
export http_proxy=http://username:password@proxyhost:port/
export ftp_proxy=http://username:password@proxyhost:port/
Save and exit the file
Update the source list and you can restart your system
sudo apt-get update

