apt.conf configuration on Ubuntu

This is sound very simple, but sometimes we forget the configuration. I just documented this, so if I forget, I can easily find how to configure apt.conf on Ubuntu. Here is the configuration:

Acquire::http::Proxy "http://(username):(password)@(name_of_the_proxy):8080";

Here is the example:
If we use proxy:cache1.itb.ac.id.
username:komang,
password:aswantara,
and then the configuration will be:

Acquire::http::Proxy "http://komang:adiaswantara@cache1.itb.ac.id:8080";

After we change, and then save the configuration. Now, you can use apt command to make update of your Ubuntu.