Setting Proxy for apt-get in Ubuntu

1. Open terminal
2. Type this
   

   sudo nano /etc/apt/apt.conf

3. Add this line if there in no authentication in your proxy
   

   Acquire::http::proxy "http://proxyserver:port/";

4. Add this if there is authentication in your proxy
   

   Acquire::http::proxy "http://username:password@proxyserver:port/";

5. Press Ctrl+x and then press y