linux: setting up traffic to go through proxy server

1. for browser: should be able to edit them via the preferences section.

2. command line:

export http_proxy="http://username:password@proxy:port/"
export https_proxy="ftp://username:password@proxy:port/"
export ftp_proxy="https://username:password@proxy:port/"

we should be able to automate this by adding to ~/.bashrc

3. apt:
In /etc/apt/apt.conf.d/80oproxy, add

Acquire::http::proxy "http://username:password@proxy:port/";
Acquire::ftp::proxy "ftp://username:password@proxy:port/";
Acquire::https::proxy "https://username:password@proxy:port/";