三种方法

-o选项

# sudo apt-get -o Acquire::http::proxy="http://127.0.0.1:8080/" update

配置文件

# vi /etc/apt/apt.conf
 
Acquire::http::proxy "http://127.0.0.1:8080/";
Acquire::ftp::proxy "ftp://127.0.0.1:8080/";
Acquire::https::proxy "https://127.0.0.1:8080/";

环境变量
据说9.10以前版本才支持

export http_proxy=http://127.0.0.1:8080