ubuntu 把软件源修改为国内源和更新（转载）
1. 备份原始文件
sudo cp /etc/apt/sources.list /etc/apt/sources.list.backup
2. 修改文件并添加国内源
vi /etc/apt/sources.list
3. 注释原文件内的源并添加如下地址
#Ubuntu 官方源 deb http://archive.ubuntu.com/ubuntu/ gutsy main restricted universe multiverse deb http://archive.ubuntu.com/ubuntu/ gutsy-security main restricted universe multiverse deb http://archive.ubuntu.com/ubuntu/ gutsy-updates main restricted universe multiverse deb http://archive.ubuntu.com/ubuntu/ gutsy-proposed main restricted universe multiverse deb http://archive.ubuntu.com/ubuntu/ gutsy-backports main restricted universe multiverse deb-src http://archive.ubuntu.com/ubuntu/ gutsy main restricted universe multiverse deb-src http://archive.ubuntu.com/ubuntu/ gutsy-security main restricted universe multiverse deb-src http://archive.ubuntu.com/ubuntu/ gutsy-updates main restricted universe multiverse deb-src http://archive.ubuntu.com/ubuntu/ gutsy-proposed main restricted universe multiverse deb-src http://archive.ubuntu.com/ubuntu/ gutsy-backports main restricted universe multiverse
#或者这些源
#阿里云 deb http://mirrors.aliyun.com/ubuntu/ trusty main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ trusty-security main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ trusty-updates main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ trusty-proposed main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ trusty-backports main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ trusty main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ trusty-security main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ trusty-updates main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ trusty-proposed main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ trusty-backports main restricted universe multiverse #网易163 deb http://mirrors.163.com/ubuntu/ trusty main restricted universe multiverse 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-src http://mirrors.163.com/ubuntu/ trusty main restricted universe multiverse deb-src http://mirrors.163.com/ubuntu/ trusty-security main restricted universe multiverse deb-src http://mirrors.163.com/ubuntu/ trusty-updates main restricted universe multiverse deb-src http://mirrors.163.com/ubuntu/ trusty-proposed main restricted universe multiverse deb-src http://mirrors.163.com/ubuntu/ trusty-backports main restricted universe multiverse
4. 放置非官方源的包不完整，可在为不添加官方源
deb http://archive.ubuntu.org.cn/ubuntu-cn/ feisty main restricted universe multiverse
5. 更新源
sudo apt-get update
6. 更新软件
sudo apt-get dist-upgrade
sudo apt-get upgrade
由于包与包之间存在各种依赖关系。upgrade只是简单的更新包，不管这些依赖，它不和添加包，或是删除包。而dist-upgrade可以根据依赖关系的变化，添加包，删除包。upgrade:系统将现有的Package升级,如果有相依性的问题,而此相依性需要安装其它新的Package或影响到其它Package的相依性时,此Package就不会被升级,会保留下来. dist-upgrade:可以聪明的解决相依性的问题,如果有相依性问题,需要安装/移除新的Package,就会试着去安装/移除它. (所以通常这个会被认为是有点风险的升级)
7. 常见的修复安装命令
sudo apt-get -f install
