sudo vi /etc/apt/sources.list
A)sudo vi /etc/apt/sources.list使用如下内容覆盖：
deb http://mirrors.163.com/ubuntu/ trusty main restricted universe multiverse #只保留163的源（最快）
deb http://mirrors.163.com/ubuntu/ trusty-security main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ trusty-updates main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ trusty-proposed main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ trusty-backports main restricted universe multiverse
deb http://download.tizen.org/tools/latest-release/Ubuntu_14.04/ / #至关重要，我们Tizen开发的gbs,sdb等工具都要从那里下载：
# --优先到ubuntu正式版本目录查看版本镜像： http://download.tizen.org/tools/latest-release/
# --没有再到ubuntu中间版本目录查看版本镜像： http://download.tizen.org/tools/archive
B)sudo apt-get update
C)sudo apt-get install ssh ##安装SSH协议支持