How To Add Proxy Authentication In Ubuntu

To add Proxy Authentication in Ubuntu First of all you have to do :

1:Go to Terminal By pressing the keys (ctrl+alt+T)
2: In terminal window Type  sudo gedit /etc/apt/apt.conf
3: A text editor will appear
4: And Add there

Acquire::http::Proxy "http://username:password@proxyhost:port/";
Acquire::https::Proxy "https://username:password@proxyhost:port/";
Acquire::ftp::Proxy "ftp://username:password@proxyhost:port/";
Acquire::http::Proxy "http://username:password@proxyhost:port/";

5:put your "proxy" in proxyhost field, "port number" in port field,"username" in username field and    "password"  in password field as mentioned above.
6 : save that file.
7: After that you are done.

If Any Issues comment below...!!