更新你的OEL

windows下有自动更新的功能，linux下也有，对应的RHL你需要有购买服务，CentOS则免费更新,那么OEL呢，也是有的，只要你配置好了。
参考：http://docs.oracle.com/cd/E21928_01/html/821-3629/gkgfr.html。我使用的是第2种方式：使用 Oracle 公共 yum 服务器和 yum 客户机来安装更新，注意这个方式只能按照原有安装包内包含的内容，如果你需要安装而外的包和内容的话，采用第1中方式，掏钱吧。
[root@EL57 ~]# cat /etc/issue
Oracle Linux Server release 5.7
Kernel \r on an \m

[root@EL57 ~]# cd cd /etc/yum.repos.d
-bash: cd: cd: 没有那个文件或目录
[root@EL57 ~]# cd /etc/yum.repos.d
[root@EL57 yum.repos.d]# wget http://public-yum.oracle.com/public-yum-el5.repo
--2012-01-14 15:30:49-- http://public-yum.oracle.com/public-yum-el5.repo
正在解析主机 public-yum.oracle.com... 141.146.44.34
Connecting to public-yum.oracle.com|141.146.44.34|:80... 已连接。
已发出 HTTP 请求，正在等待回应... 200 OK
长度：2533 (2.5K) [text/plain]
Saving to: `public-yum-el5.repo'

100%[==========================================================================>] 2,533 --.-K/s in 0s

2012-01-14 15:30:50 (155 MB/s) - `public-yum-el5.repo' saved [2533/2533]

[root@EL57 yum.repos.d]# ls
public-yum-el5.repo
将public-yum-el5.repo文件中的enabled=0改成enabled=1保存退出vi，这个地方最好只把你需要使用的更新源修改启用即可。
[root@EL57 yum.repos.d]# yum list
将开始更新资料库，这个过程可以需要花费几分钟的时间，更新完成后就可以安装了，比如我要安装vsftpd。
[root@EL57 yum.repos.d]# rpm -qa | grep vsftpd
[root@EL57 yum.repos.d]# yum install vsftpd
Loaded plugins: rhnplugin, security
This system is not registered with ULN.
ULN support will be disabled.
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package vsftpd.i386 0:2.0.5-21.el5 set to be updated
ol5_u7_base/filelists | 2.8 MB 03:07
--> Finished Dependency Resolution

Dependencies Resolved

======================================================================================================================================================================================
Package Arch Version Repository Size
======================================================================================================================================================================================
Installing:
vsftpd i386 2.0.5-21.el5 ol5_u7_base 142 k

Transaction Summary
======================================================================================================================================================================================
Install 1 Package(s)
Upgrade 0 Package(s)

Total download size: 142 k
Is this ok [y/N]:
Downloading Packages:
vsftpd-2.0.5-21.el5.i386.rpm | 142 kB 00:07
warning: rpmts_HdrFromFdno: Header V3 DSA signature: NOKEY, key ID 1e5e0159
ol5_u7_base/gpgkey | 1.4 kB 00:00
Importing GPG key 0x1E5E0159 "Oracle OSS group (Open Source Software group) <[e-mail]>" from http://public-yum.oracle.com/RPM-GPG-KEY-oracle-el5
Is this ok [y/N]: y
Running rpm_check_debug
Running Transaction Test
Finished Transaction Test
Transaction Test Succeeded
Running Transaction
Installing : vsftpd 1/1

Installed:
vsftpd.i386 0:2.0.5-21.el5

Complete!
ok，已经安装完成了，检查下：
[root@EL57 yum.repos.d]# rpm -qa | grep vsftpd
vsftpd-2.0.5-21.el5
[root@EL57 yum.repos.d]#
cool，这样再也不用到处找安装包了吧，而且还可以自动解决依赖性的问题。
-The End-