Proxyon

http_proxy=http://www-proxy.us.oracle.com:80/
no_proxy="localhost,127.0.0.1,.us.oracle.com,.cn.oracle.com,10.0.0.0/8,172.16.0.0/12,192.168.0.0/16"

export http_proxy
export https_proxy=$http_proxy
export ftp_proxy=$http_proxy
export HTTPS_PROXY=$http_proxy
export HTTP_PROXY=$http_proxy
export FTP_PROXY=$http_proxy
export no_proxy
export NO_PROXY=$no_proxy

proxy off

unset http_proxy
unset https_proxy
unset ftp_proxy
unset HTTPS_PROXY
unset HTTP_PROXY
unset FTP_PROXY

proxy for sudo

cat /etc/sudoers.d/proxy
Defaults env_keep += "HTTP_PROXY HTTPS_PROXY FTP_PROXY NO_PROXY"
Defaults env_keep += "http_proxy https_proxy ftp_proxy no_proxy"