记一下安装centos时的注意事项，供以后查阅
什么是live cd?
live cd的意思是免安装版。用live cd意味着直接在光盘上跑centos
centos 5有8张cd, 我都要下吗？
不必，centos 必须的功能都在第一张盘里，下载第一张盘即可. 安装时要这样:
You can do a minimal install that just requires the first CD by performing the following two steps during the installation:
* During the category/task selection, deselect all package categories, and choose the "Customize now" option at the bottom of screen.
* During the customized package selection, deselect everything ( including the Base group ).
遇到错误：The CentOS disc was not found in any of your drives …
"One solution is to reboot and choose to skip the media test"
最小安装后需要添加的包
最小安装后，你会发现连"man"命令都用不了，因为此时的包实在太少。
你可能想添加的包有：
yum groupinstall base
看看哪个包里面有我要的命令，再安装这个包
yum whatprovides */ifconfig
路径设置
#非root用户把sbin纳入路径
export PATH=$PATH:/sbin
把epel纳入到yum库中
有些著名的包在标准repository里找不到，而是收录在epel里。
su -c ‘rpm -Uvh http://download.fedoraproject.org/pub/epel/5/i386/epel-release-5-4.noarch.rpm’