yum只下载不安装

请确认yum-downloadonly包已经安装。如果没有安装，可以从红帽网络（RHN） 下载【通过下边的命令可以安装】。如果系统已经注册到RHN，可以执行以下命令安装yum-downloadonly包：

#yum install yum-downloadonly
yum-downloadonly是yum的一个插件，使得yum可以从RHN或者yum的仓库只下载包而不安装。 检查一下/etc/yum/pluginconf.d/downloadonly.conf的内容，确认这个插件已经启用：

[main]
enabled=1
例如我们要下载vsftpd的最新版本，而不安装它，执行命令：

# yum install --downloadonly vsftpd
Loading "downloadonly" plugin
Loading "rhnplugin" plugin
rhel-i386-server-5 100% |=========================| 1.4 kB 00:00
Setting up Install Process
Parsing package install arguments
Package vsftpd - 2.0.5-10.el5.i386 is already installed.
Resolving Dependencies
--> Running transaction check
---> Package vsftpd.i386 0:2.0.5-12.el5 set to be updated
--> Finished Dependency Resolution

Dependencies Resolved

=============================================================================
Package Arch Version Repository Size
====!
=========================================================================
Updating:
vsftpd i386 2.0.5-12.el5 rhel-i386-server-5 138 k

Transaction Summary
=============================================================================
Install 0 Package(s)
Update 1 Package(s)
Remove 0 Package(s)

Total download size: 138 k
Is this ok [y/N]: y
Downloading Packages:
(1/1): vsftpd-2.0.5-12.el 100% |=========================| 138 kB 00:02

exiting because --downloadonly specified
默认的，包会被报存在/var/cache/yum/{RepositoryName}/packages/目录中。在这里 {RepositoryName}是rhel-i386-server-5【我的是fedora】。指定yum的参数--downloaddir，和 --downloadonly一并使用，来指定另外的目录来存放下载的包。

#yum install --downloadonly --downloaddir=/tmp vsftpd