引子：

ubuntu 64位系统需要，在某些程序用到ia32-libs库！

执行安装提示错误 ,或者提示404 Not Found

sudo apt-get install ia32-libs
[sudo] password for andy: 
Reading package lists… Done
Building dependency tree       
Reading state information… Done
Package ia32-libs is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
However the following packages replace it:
  lib32z1 lib32ncurses5 lib32bz2-1.0

解决方法:

sudo -i
cd /etc/apt/sources.list.d
echo “deb http://mirrors.ustc.edu.cn/ubuntu-old-releases/ubuntu/ raring main restricted universe multiverse” >ia32-libs-raring.list
apt-get update
apt-get install ia32-libs
rm ia32-libs-raring.list

总结:

上面是用中国科学技术大学镜像，所以速度很快的更新下来，另：官方的镜像地址更改，所以会说官方的ip找不到！。