ubuntu软件源的一些问题

使用apt-get install时经常会出现下面的报错
“404 not found 或者 failed to fetch”
解决这个问题可以从下面几个方面考虑:

1. 是否可以上网
2. 用apt-get update ，然后再试试apt-get install
   如果apt-get update 也出现很多 404 not found 或者 failed to fetch ，就要考虑更换自己的源，百度搜 /etc/apt/sources.list
3. ubuntu版本过低

下面说下如何手动更换apt-get的软件源路径

    1）首先备份一下源列表，sudo cp /etc/apt/sources.list /etc/apt/sources.list.backup 

    2）修改更新源，sudo vi /etc/apt/sources.list 添加源：

        #电子科技大学 （教育网）
        deb http://ubuntu.uestc.edu.cn/ubuntu/ oneiric main restricted universe multiverse 
        deb http://ubuntu.uestc.edu.cn/ubuntu/ oneiric-backports main restricted universe multiverse 
        deb http://ubuntu.uestc.edu.cn/ubuntu/ oneiric-proposed main restricted universe multiverse 
        deb http://ubuntu.uestc.edu.cn/ubuntu/ oneiric-security main restricted universe multiverse 
        deb http://ubuntu.uestc.edu.cn/ubuntu/ oneiric-updates main restricted universe multiverse 
        deb-src http://ubuntu.uestc.edu.cn/ubuntu/ oneiric main restricted universe multiverse 
        deb-src http://ubuntu.uestc.edu.cn/ubuntu/ oneiric-backports main restricted universe multiverse 
        deb-src http://ubuntu.uestc.edu.cn/ubuntu/ oneiric-proposed main restricted universe multiverse 
        deb-src http://ubuntu.uestc.edu.cn/ubuntu/ oneiric-security main restricted universe multiverse 
        deb-src http://ubuntu.uestc.edu.cn/ubuntu/ oneiric-updates main restricted universe multiverse

        #中国科技大学 
        deb http://mirrors.ustc.edu.cn/ubuntu/ oneiric main restricted universe multiverse 
        deb http://mirrors.ustc.edu.cn/ubuntu/ oneiric-backports restricted universe multiverse 
        deb http://mirrors.ustc.edu.cn/ubuntu/ oneiric-proposed main restricted universe multiverse 
        deb http://mirrors.ustc.edu.cn/ubuntu/ oneiric-security main restricted universe multiverse 
        deb http://mirrors.ustc.edu.cn/ubuntu/ oneiric-updates main restricted universe multiverse 
        deb-src http://mirrors.ustc.edu.cn/ubuntu/ oneiric main restricted universe multiverse 
        deb-src http://mirrors.ustc.edu.cn/ubuntu/ oneiric-backports main restricted universe multiverse 
        deb-src http://mirrors.ustc.edu.cn/ubuntu/ oneiric-proposed main restricted universe multiverse 
        deb-src http://mirrors.ustc.edu.cn/ubuntu/ oneiric-security main restricted universe multiverse 
        deb-src http://mirrors.ustc.edu.cn/ubuntu/ oneiric-updates main restricted universe multiverse

        #网易 Ubuntu 11.10 源（速度很快） 
        deb http://mirrors.163.com/ubuntu/ oneiric main universe restricted multiverse 
        deb-src http://mirrors.163.com/ubuntu/ oneiric main universe restricted multiverse 
        deb http://mirrors.163.com/ubuntu/ oneiric-security universe main multiverse restricted 
        deb-src http://mirrors.163.com/ubuntu/ oneiric-security universe main multiverse restricted 
        deb http://mirrors.163.com/ubuntu/ oneiric-updates universe main multiverse restricted 
        deb http://mirrors.163.com/ubuntu/ oneiric-proposed universe main multiverse restricted 
        deb-src http://mirrors.163.com/ubuntu/ oneiric-proposed universe main multiverse restricted 
        deb http://mirrors.163.com/ubuntu/ oneiric-backports universe main multiverse restricted 
        deb-src http://mirrors.163.com/ubuntu/ oneiric-backports universe main multiverse restricted 
        deb-src http://mirrors.163.com/ubuntu/ oneiric-updates universe main multiverse restricted

        #这里你也可以直接使用更快速的ubuntu.cn99.com的源（推荐）:
        deb http://ubuntu.cn99.com/ubuntu/ oneiric main restricted universe multiverse
        deb http://ubuntu.cn99.com/ubuntu/ oneiric-updates main restricted universe multiverse
        deb http://ubuntu.cn99.com/ubuntu/ oneiric-security main restricted universe multiverse
        deb http://ubuntu.cn99.com/ubuntu/ oneiric-backports main restricted universe multiverse
        deb http://ubuntu.cn99.com/ubuntu-cn/ oneiric main restricted universe multiverse

    3) 通知ubuntu启用新的更新源   sudo apt-get update

以上内容参考了文章:
http://www.mamicode.com/info-detail-419935.html
http://www.cnblogs.com/nexiyi/archive/2013/01/06/2847166.html