当运行apt-get update后出现如下错误时：
出现了某些故障（-5 - 没有与主机名关联的地址）
E: Some index files Failed to download,they have been ignored,or old ones used instead.
可以将目录下/var/lib/apt/lists/partial/所有的文件清掉，再次运行apt-get update即可！
如果还有问题，请检查resolvconf服务的配置文件: /etc/resolvconf/resolv.conf.d/base ， 很可能是DNS的问题，可以使用公共的dns地址：
nameserver 8.8.8.8
nameserver 4.2.2.2

Ubuntu12.04自带源在大陆不好。可以更换其他源：
如果是其它ubuntu版本，只需把precise改为相应的版本的名字。hardy(8.04),lucid(10.04),maverick(10.10),oneiric(11.10),quantal(12.10),precise(12.04) trusty(14.04)
/etc/apt/sources.list

163

deb http://mirrors.163.com/ubuntu/ precise main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ precise-security main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ precise-updates main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ precise-proposed main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ precise-backports main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ precise main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ precise-security main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ precise-updates main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ precise-proposed main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/precise-backports main restricted universe multiverse

sohu

deb http://mirrors.sohu.com/ubuntu/ precise main restricted universe multiverse
deb http://mirrors.sohu.com/ubuntu/ precise-security main restricted universe multiverse
deb http://mirrors.sohu.com/ubuntu/ precise-updates main restricted universe multiverse
deb http://mirrors.sohu.com/ubuntu/ precise-proposed main restricted universe multiverse
deb http://mirrors.sohu.com/ubuntu/ precise-backports main restricted universe multiverse
deb-src http://mirrors.sohu.com/ubuntu/ precise main restricted universe multiverse
deb-src http://mirrors.sohu.com/ubuntu/ precisec-security main restricted universe multiverse
deb-src http://mirrors.sohu.com/ubuntu/ precise-updates main restricted universe multiverse
deb-src http://mirrors.sohu.com/ubuntu/ precise-proposed main restricted universe multiverse
deb-src http://mirrors.sohu.com/ubuntu/ precise-backports main restricted universe multiverse

ustc

deb http://mirrors.ustc.edu.cn/ubuntu/ precise main restricted universe multiverse
deb http://mirrors.ustc.edu.cn/ubuntu/ precise-security main restricted universe multiverse
deb http://mirrors.ustc.edu.cn/ubuntu/ precise-updates main restricted universe multiverse
deb http://mirrors.ustc.edu.cn/ubuntu/ precise-proposed main restricted universe multiverse
deb http://mirrors.ustc.edu.cn/ubuntu/ precise-backports main restricted universe multiverse
deb-src http://mirrors.ustc.edu.cn/ubuntu/ precise main restricted universe multiverse
deb-src http://mirrors.ustc.edu.cn/ubuntu/ precise-security main restricted universe multiverse
deb-src http://mirrors.ustc.edu.cn/ubuntu/ precise-updates main restricted universe multiverse
deb-src http://mirrors.ustc.edu.cn/ubuntu/ precise-proposed main restricted universe multiverse
deb-src http://mirrors.ustc.edu.cn/ubuntu/ precise-backports main restricted universe multiverse