/etc/environment 中添加以下内容，就可以为系统制定全局的 http 代理
http_proxy="http://127.0.0.1:8087"
https_proxy="http://127.0.0.1:8087"
These programs will not obey the environment variables either. Create a file called 95proxies in/etc/apt/apt.conf.d/, and include the following:
Acquire::http::proxy "http://myproxy.server.com:8080/";
Acquire::ftp::proxy "ftp://myproxy.server.com:8080/";
Acquire::https::proxy "https://myproxy.server.com:8080/";