快速换源更新到Ubuntu 15.04的方法

sudo cp /etc/apt/sources.list /etc/apt/sources.list.backup

sudo gedit /etc/apt/sources.list

将下面的代码粘贴进去（“#”开头的那一行为注释，可以直接复制进文件中）

#网易源：

deb http://mirrors.163.com/ubuntu/ vivid main restricted universe multiverse

deb http://mirrors.163.com/ubuntu/ vivid-security main restricted universe multiverse

deb http://mirrors.163.com/ubuntu/ vivid-updates main restricted universe multiverse

deb http://mirrors.163.com/ubuntu/ vivid-proposed main restricted universe multiverse

deb http://mirrors.163.com/ href="http://cpro.baidu.com/cpro/ui/uijs.php?adclass=0&app_id=0&c=news&cf=1001&ch=0&di=128&fv=0&is_app=0&jk=a63393fc0b194c4c&k=ubuntu&k0=ubuntu&kdi0=0&luki=1&mcpm=0&n=10&p=baidu&q=smileking_cpr&rb=0&rs=1&seller_id=1&sid=4c4c190bfc9333a6&ssp2=1&stid=9&t=tpclicked3_hc&td=1682280&tu=u1682280&u=http%3A%2F%2Fwww%2Eth7%2Ecn%2Fsystem%2Flin%2F201507%2F119815%2Eshtml&urlid=0" target=_blank>ubuntu/
vivid-backports main restricted universe multiverse

deb-src http://mirrors.163.com/ubuntu/ vivid main restricted universe multiverse

deb-src http://mirrors.163.com/ubuntu/ vivid-security main restricted universe multiverse

deb-src http://mirrors.163.com/ubuntu/ vivid-updates main restricted universe multiverse

deb-src http://mirrors.163.com/ubuntu/ vivid-proposed main restricted universe multiverse

deb-src http://mirrors.163.com/ href="http://cpro.baidu.com/cpro/ui/uijs.php?adclass=0&app_id=0&c=news&cf=1001&ch=0&di=128&fv=0&is_app=0&jk=a63393fc0b194c4c&k=ubuntu&k0=ubuntu&kdi0=0&luki=1&mcpm=0&n=10&p=baidu&q=smileking_cpr&rb=0&rs=1&seller_id=1&sid=4c4c190bfc9333a6&ssp2=1&stid=9&t=tpclicked3_hc&td=1682280&tu=u1682280&u=http%3A%2F%2Fwww%2Eth7%2Ecn%2Fsystem%2Flin%2F201507%2F119815%2Eshtml&urlid=0" target=_blank>ubuntu/
vivid-backports main restricted universe multiverse

刷新源：sudo apt-get update

更新：sudo update-manager -c -d