$ curl example.com -x http://<auth-username>:<auth-password>@<proxy-host>:<proxy-port>
export http_proxy=http://username:password@192.168.1.1:3214
export https_proxy=http://username:password@192.168.1.1:3214
$ curl example.com -x http://<auth-username>:<auth-password>@<proxy-host>:<proxy-port>
export http_proxy=http://username:password@192.168.1.1:3214
export https_proxy=http://username:password@192.168.1.1:3214