Replace your proxy hostname and port number instead of webcache.cs.bham.ac.uk:3128
below.
Set the following in your .bashrc
file:
export HTTP_PROXY=http://webcache.cs.bham.ac.uk:3128
export HTTPS_PROXY=http://webcache.cs.bham.ac.uk:3128
export FTP_PROXY=http://webcache.cs.bham.ac.uk:3128