ubuntu默認使用的國外的源，在更新的時候會很慢，可以使用國內的阿里的源,那效率和速度,你知道的~
1.先備份文件
sudo cp /etc/apt/sources.list /etc/apt/sources.list.bak
2.清空
sudo > /etc/apt/sources.list
3.寫入
sudo vim /etc/apt/sources.list
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
備註: 如果報錯 command not found ,說明沒有安裝vim編輯器,使用命令：sudo apt-get install vim 安裝即可
4.更新
sudo apt-get update&&sudo apt-get upgrade&&sudo apt-get install -f
更新ing ...
Get:62 http://mirrors.aliyun.com/ubuntu trusty-backports/universe i386 Packages [43.2 kB]
Get:63 http://mirrors.aliyun.com/ubuntu trusty-backports/universe amd64 Packages [43.1 kB]
Get:64 http://mirrors.aliyun.com/ubuntu trusty-backports/universe Translation-en [36.8 kB]
Get:65 http://mirrors.aliyun.com/ubuntu trusty-backports/multiverse amd64 Packages [1,567 B]
Get:66 http://mirrors.aliyun.com/ubuntu trusty-backports/multiverse i386 Packages [1,551 B]
Get:67 http://mirrors.aliyun.com/ubuntu trusty-backports/multiverse Translation-en [1,215 B]
Get:68 http://mirrors.aliyun.com/ubuntu trusty/restricted Sources [5,433 B]
Get:69 http://mirrors.aliyun.com/ubuntu trusty/universe Sources [6,399 kB]
Get:70 http://mirrors.aliyun.com/ubuntu trusty/multiverse Sources [174 kB]
Get:71 http://mirrors.aliyun.com/ubuntu trusty/main Sources [1,064 kB]
Get:72 http://mirrors.aliyun.com/ubuntu trusty/main amd64 Packages [1,350 kB]
Get:73 http://mirrors.aliyun.com/ubuntu trusty/main i386 Packages [1,348 kB]
Get:74 http://mirrors.aliyun.com/ubuntu trusty/restricted amd64 Packages [13.0 kB]
Get:75 http://mirrors.aliyun.com/ubuntu trusty/restricted i386 Packages [13.4 kB]
Get:76 http://mirrors.aliyun.com/ubuntu trusty/universe amd64 Packages [5,859 kB]
Get:77 http://mirrors.aliyun.com/ubuntu trusty/universe i386 Packages [5,866 kB]
Get:78 http://mirrors.aliyun.com/ubuntu trusty/multiverse i386 Packages [134 kB]
Get:79 http://mirrors.aliyun.com/ubuntu trusty/multiverse amd64 Packages [132 kB]
Fetched 30.3 MB in 34s (896 kB/s)
Reading package lists... Done