CentOS 配置yum源

# vi /etc/yum.respos.d/CentOS-Base.repo

将内容改为（横线内，不包括横线）：

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[base] 
name=CentOS-$releasever - Base 
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os
baseurl=http://centos.ustc.edu.cn/centos/$releasever/os/$basearch/ 
gpgcheck=1
gpgkey=http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-5  

#released updates  [updates] 
name=CentOS-$releasever - Updates 
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=updates
baseurl=http://centos.ustc.edu.cn/centos/$releasever/updates/$basearch/ 
gpgcheck=1
gpgkey=http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-5  

#packages used/produced in the build but not released 
[addons] 
name=CentOS-$releasever - Addons 
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=addons
baseurl=http://centos.ustc.edu.cn/centos/$releasever/addons/$basearch/ 
gpgcheck=1
gpgkey=http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-5  

#additional packages that may be useful 
[extras] 
name=CentOS-$releasever - Extras 
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=extras
baseurl=http://centos.ustc.edu.cn/centos/$releasever/extras/$basearch/ 
gpgcheck=1
gpgkey=http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-5 

#additional packages that extend functionality of existing packages 
[centosplus] 
name=CentOS-$releasever - Plus 
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=centosplus
baseurl=http://centos.ustc.edu.cn/centos/$releasever/centosplus/$basearch/ 
gpgcheck=1
enabled=0
gpgkey=http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-5

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保存退出。

升级系统。

# yum -y update

屏幕一阵跳动，Complete!  升级完毕。