建立文件夹
[root@localhost CentOS]# mkdir /media/CentOS
把光盘加载到本地
[root@localhost CentOS]# mount /dev/cdrom /media/CentOS
在/etc/yum.repos.d/目录下，有两个文件
CentOS-Base.repo和CentOS-Media.repo
其中CentOS-Base.repo记录着网络上的yum源的地址和路径信息等
CentOS-Media.repo记录着可以从本地作为yum源的介质和路径。其中还有这样一个说明：
# CentOS-Media.repo
#
# This repo is used to mount the default locations for a CDROM / DVD on
# CentOS-5. You can use this repo and yum to install items directly off the
# DVD ISO that we release.
#
# To use this repo, put in your DVD and use it with the other repos too:
# yum --enablerepo=c5-media [command]
#
# or for ONLY the media repo, do this:
#
# yum --disablerepo=\* --enablerepo=c5-media [command]
[c5-media]
name=CentOS-$releasever - Media
baseurl=file:///media/ CentOS
gpgcheck=1
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-beta
我们只需编辑下bashurl ，将自己的光盘路径写入就可以了。
觉得自己的光盘的源足够用了。不需要网络源，或者没有网络。
可以使用yum --disablerepo=\* --enablerepo=c5-media [command]
yum命令允许使用本地media介质的源而已。正确的命令如下（更新gcc为例）：
[root@centos cdrom]# yum --disablerepo =* --enablerepo=c5-media install gcc
Loading " installonlyn " plugin
Setting up Update Process
Setting up repositories
c5 - media 100 % |=========================| 1.1 kB 00 : 00
Reading repository metadata in from local files
primary.xml.gz 100 % |=========================| 834 kB 00 : 00
################################################## 2400 / 2400
No Packages marked for Update / Obsoletion
比如安装gdb
[root@centos cdrom]# yum --disablerepo =* --enablerepo=c5-media install gdb
Loading " installonlyn " plugin
Setting up Install Process
Setting up repositories
Reading repository metadata in from local files
Parsing package install arguments
Resolving Dependencies
Populating transaction set with selected packages. Please wait.
Downloading header for gdb to pack into transaction set .
gdb - 6.5 - 25 .el5.i386.rpm 100 % |=========================| 56 kB 00 : 00
Package gdb.i386 0 : 6.5 - 25 .el5 set to be updated
Running transaction check
Dependencies Resolved
Package Arch Version Repository Size
Installing:
gdb i386 6.5 - 25 .el5 c5 - media 3.1 M
Transaction Summary
Install 1 Package(s)
Update 0 Package(s)
Remove 0 Package(s)
Total download size: 3.1 M
Is this ok [y / N]: y
Downloading Packages:
Running Transaction Test
Finished Transaction Test
Transaction Test Succeeded
Running Transaction
Installing: gdb ######################### [ 1 / 1 ]
Installed: gdb.i386 0 : 6.5 - 25 .el5
Complete !
[root@centos cdrom]#
在使用yum进行install时，经常会出现下面的错误
warning: rpmts_HdrFromFdno: Header V3 DSA signature: NOKEY, key ID 1ac70ce6
导致安装不能进行。解决方法如下：
[root@localhost CentOS]# rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-5
[root@localhost CentOS]# rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-beta