Linux: Set Proxy in APT and WGET on Debian/Ubuntu Linux

1. Edit apt.conf.

vi /etc/apt/apt.conf

2. Add the proxy address.

Acquire::http::proxy "http://PROXY-ADDRESS:PORT/";
Acquire::https::proxy "https://PROXY-ADDRESS:PORT/";
Acquire::ftp::proxy "ftp://PROXY-ADDRESS:PORT/";

3. Test apt command.

apt update

4. Edit wgetrc.

vi /etc/wgetrc

5. Uncomment the line pertaining to proxy and use the proxy.

6. Test wget command.

wget https://download.sublimetext.com/sublime_text_3_build_3126_x64.tar.bz2