Ubuntu代理设置及apt-get

切换到root用户
someuser@u-bigboy:~$ sudo su -

增加sudo用户
vi /etc/sudoer

增加代理
sudo /etc/apt/apt.conf
acquire::http::proxy "http://username:passowrd@proxy:80/";

更新Software
sudo apt-get update
sudo apt-get upgrade

sudo apt-get install/remove openssh-server  Ubuntu
sudo apt-get install/remove vim  Ubuntu
or
sudo yum install/remove openssh-server   CentOS

cp -r /root/ /mnt   /*将/root目录中的所有文件及其子目录拷贝到目录/mnt中*/