If you have a Ubuntu 10.04 LTS (Lucid Lynx) installation behind a proxy and you would like to use APT-GET and WGET then the below modifications need to be implemented:

Modifying apt.conf:

# sudo nano /etc/apt/apt.conf

And add these two lines:

Acquire::http::Proxy "http://user:pass@proxy-host:port/";
Acquire::ftp::Proxy "http://user:pass@proxy-host:port/";

If a username and password is not required, simply remove them as so:

Acquire::http::Proxy "http://proxy-host:port/";
Acquire::ftp::Proxy "http://proxy-host:port/";

Save & exit.

Modiying WGET

Simply run the below command:

# echo "export http_proxy=http://user:pass@proxy-host:port/" | tee -a ~/.bashrc

If there isn’t a username or password:

# echo "export http_proxy=http://proxy-host:port/" | tee -a ~/.bashrc

Done!