ubuntu 换源过程中遇到的坑(一):Could not resolve 'mirrors.aliyun.com'

执行更新数据(sudo apt-get update)提示:

Err http://mirrors.aliyun.com trusty Release.gpg
  Could not resolve 'mirrors.aliyun.com'
Err http://mirrors.aliyun.com trusty-updates Release.gpg
  Could not resolve 'mirrors.aliyun.com'
Err http://mirrors.aliyun.com trusty-backports Release.gpg
  Could not resolve 'mirrors.aliyun.com'
Err http://mirrors.aliyun.com trusty-security Release.gpg
  Could not resolve 'mirrors.aliyun.com'
Reading package lists... Done
W: Failed to fetch http://mirrors.aliyun.com/ubuntu/dists/trusty/InRelease

此时只要编辑网络DNS配置文件即可: 

sudo gedit /etc/resolv.conf

在弹出的文本里最下面加入:

cat /etc/resolv.conf
# 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

重启网络：

sudo /etc/init.d/networking restart

再次执行3步:

sudo apt-get update

执行完成,然后:

sudo apt-get upgrade

大功告成!

(接下来步骤,详见此文接第5步):https://www.cnblogs.com/chenxi188/p/10620775.html

参考:https://blog.csdn.net/ronghua_liu/article/details/8609450

　　https://www.jianshu.com/p/486e7f9802ab