本文转载自：http://www.jianshu.com/p/0de2b5717ce8
1 $ sudo apt-get update
报了一堆错误：
Err http://cn.archive.ubuntu.com trusty InRelease
Err http://cn.archive.ubuntu.com trusty-updates InRelease
Err http://cn.archive.ubuntu.com trusty-backports InRelease
Err http://cn.archive.ubuntu.com trusty Release.gpg
W: Failed to fetch http://cn.archive.ubuntu.com/ubuntu/dists/trusty/InRelease解决方案： 修改DNS
sudo vi /etc/resolvconf/resolv.conf.d/base在里面插入：
nameserver 8.8.8.8
nameserver 8.8.4.4修改好保存!wq，
然后执行
$ sudo resolvconf -u再看 /etc/resolv.conf，最下面就多了2行：
$ cat /etc/resolv.conf显示
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
# DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
nameserver 8.8.8.8
nameserver 8.8.4.4此时执行
$ sudo apt-get update可以运行，然后就可以使用sudo apt-get install **指令了。