Linux常用指令

临时生效（当前终端）：
export http_proxy="http://IP:端口"
export https_proxy="http://IP:端口"

永久生效（写入配置文件）：
echo 'export http_proxy="http://IP:端口"' >> ~/.bashrc
echo 'export https_proxy="http://IP:端口"' >> ~/.bashrc
source ~/.bashrc

取消代理：
unset http_proxy https_proxy