How to set up Linux system proxy

Type the following command to set proxy server:

export http_proxy=http://server-ip:port/
export http_proxy=http://127.0.0.1:3128/
export http_proxy=http://proxyserver.org:3128/

For https:

export http_proxy=http://server-ip:port/

 Set system proxy permanently to all system users: 

Write the previous lines into /etc/enviroment

vim /etc/enviroment