轉載自 http://blog.csdn.net/zhngjan/article/details/20843465
略做修改。
'在使用redhat linux的yum來安裝或者更新軟件的時候會提示
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[admin@server1 ~]$ sudo yum install gcc
Loaded plugins: product-id, refresh-packagekit, security, subscription-manager
This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.
Setting up Install Process
No package gcc available.
Error: Nothing to do
[注]請以root身份操作
由於 redhat的yum在線更新是收費的，如果沒有註冊的話不能使用，如果要使用，需將redhat的yum卸載後，重啓安裝，再配置其他源
解決辦法：
1、首先到http://mirrors.163.com/centos下載軟件包
下面附件已經下載好了。
x86 地址：http://mirrors.163.com/centos/6/os/i386/Packages/
x86_64 地址：http://mirrors.163.com/centos/6/os/x86_64/Packages/
必要下載的軟件包有（以64位系統爲例）：
1> python-iniparse-0.3.1-2.1.el6.noarch.rpm
2> yum-3.2.29-40.el6.centos.noarch.rpm
3> yum-metadata-parser-1.1.2-16.el6.x86_64.rpm
4> yum-plugin-fastestmirror-1.1.30-14.el6.noarch.rpm
下載命令：
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wget http://mirrors.163.com/centos/6/os/x86_64/Packages/python-iniparse-0.3.1-2.1.el6.noarch.rpm
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wget http://mirrors.163.com/centos/6/os/x86_64/Packages/yum-metadata-parser-1.1.2-16.el6.x86_64.rpm
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wget http://mirrors.163.com/centos/6/os/x86_64/Packages/yum-3.2.29-40.el6.centos.noarch.rpm
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wget http://mirrors.163.com/centos/6/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.30-14.el6.noarch.rpm
[注] :版本不一定要最新的(http://mirrors.1
63.com/centos/6/os/x86_64/Packages/ 查找對應版本)
2、卸載RedHat自帶的yum
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rpm -qa | grep yum | xargs rpm -e --nodeps
注：1> xargs是一條Unix和類Unix操作系統的常用命令。它的作用是將參數列表轉換成小塊分段傳遞給其他命令，以避免參數列表過長的問題
2> --nodeps 強制卸載,不管依賴性
3、安裝下載的centos的yum包：
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rpm -ivh python-iniparse-0.3.1-2.1.el6.noarch.rpm
rpm -ivh yum-metadata-parser-1.1.2-16.el6.x86_64.rpm
rpm -ivh yum-3.2.29-40.el6.centos.noarch.rpm yum-plugin-fastestmirror-1.1.30-14.el6.noarch.rpm
[注] :最後2個需要一起安裝，否則會出現依賴性錯誤
4、到http://mirrors.163.com的 centos幫助文檔 中下載CentOS6-Base-163.repo文件，存放到/etc/yum.repo.d中
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wget http://mirrors.163.com/.help/CentOS6-Base-163.repo
5、編輯CentOS6-Base-163.repo文件，將其中的$releasever更改爲centos的版本號
下面附件已經修改好了。
下面是修改好的：
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# CentOS-Base.repo
#
# The mirror system uses the connecting IP address of the client and the
# update status of each mirror to pick mirrors that are updated to and
# geographically close to the client. You should use this for CentOS updates
# unless you are manually picking other mirrors.
#
# If the mirrorlist= does not work for you, as a fall back you can try the
# remarked out baseurl= line instead.
#
#
[base]
name=CentOS-6.5 - Base - 163.com
baseurl=http://mirrors.163.com/centos/6.5/os/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=6.5&arch=$basearch&repo=os
gpgcheck=1
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-6
#released updates
[updates]
name=CentOS-6.5 - Updates - 163.com
baseurl=http://mirrors.163.com/centos/6.5/updates/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=6.5&arch=$basearch&repo=updates
gpgcheck=1
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-6
#additional packages that may be useful
[extras]
name=CentOS-6.5 - Extras - 163.com
baseurl=http://mirrors.163.com/centos/6.5/extras/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=6.5&arch=$basearch&repo=extras
gpgcheck=1
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-6
#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-6.5 - Plus - 163.com
baseurl=http://mirrors.163.com/centos/6.5/centosplus/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=6.5&arch=$basearch&repo=centosplus
gpgcheck=1
enabled=0
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-6
#contrib - packages by Centos Users
[contrib]
name=CentOS-6.5 - Contrib - 163.com
baseurl=http://mirrors.163.com/centos/6.5/contrib/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=6.5&arch=$basearch&repo=contrib
gpgcheck=1
enabled=0
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-6
6、yum clean all 清除原有緩存
7、yum makecache 獲取yum列表
出現下面提示，表示yum更改完成：
Metadata Cache Created
8、yum update 更新yum
更新的文件放置目錄http://blog.
/var/cache/yum/x86_64/$releasever/updates/packages