apt-get not working behind socks proxy
In order for apt to work behind proxy, you need to set it in /etc/apt/apt.conf. Create this file and write the following to it:
Acquire::http::proxy "http://username:password@host:port_no/";
Acquire::https::proxy "https://username:password@host:port_no/";
Acquire::ftp::proxy "ftp://username:password@host:port_no/";
Acquire::socks::proxy "socks://username:password@host:port_no/";
Replacing username by your username and password by your password(if applicable) and host and port_no by the host of proxy and port no of your proxy.