Add the following one-liner at the end of .bashrc script:
export {http,https,ftp}_proxy='http://<user>:<password>@<proxy-server>:<port>'
For example: export {http,https,ftp}_proxy='http://10.0.2.2:3128'
For this to take effect, restart terminal or run source with . ~/.bashrc
After that, check for the presence of the environmental variables with printenv | grep proxy
yields the following output:
http_proxy=http://10.0.2.2:3128 ftp_proxy=http://10.0.2.2:3128 https_proxy=http://10.0.2.2:3128
