1. 插件安裝
yum install yum-plugin-downloadonly
2. 只下載不安裝（以安裝 perl 做 一下 演示）
yum install --downloadonly --downloaddir=/opt/perl perl
3. 查看下載文件
├── perl-5.16.3-292.el7.x86_64.rpm
├── perl-Carp-1.26-244.el7.noarch.rpm
├── perl-constant-1.27-2.el7.noarch.rpm
├── perl-Encode-2.51-7.el7.x86_64.rpm
├── perl-Exporter-5.68-3.el7.noarch.rpm
├── perl-File-Path-2.09-2.el7.noarch.rpm
├── perl-File-Temp-0.23.01-3.el7.noarch.rpm
├── perl-Filter-1.49-3.el7.x86_64.rpm
├── perl-Getopt-Long-2.40-2.el7.noarch.rpm
├── perl-HTTP-Tiny-0.033-3.el7.noarch.rpm
├── perl-libs-5.16.3-292.el7.x86_64.rpm
├── perl-macros-5.16.3-292.el7.x86_64.rpm
├── perl-parent-0.225-244.el7.noarch.rpm
├── perl-PathTools-3.40-5.el7.x86_64.rpm
├── perl-Pod-Escapes-1.04-292.el7.noarch.rpm
├── perl-podlators-2.5.1-3.el7.noarch.rpm
├── perl-Pod-Perldoc-3.20-4.el7.noarch.rpm
├── perl-Pod-Simple-3.28-4.el7.noarch.rpm
├── perl-Pod-Usage-1.63-3.el7.noarch.rpm
├── perl-Scalar-List-Utils-1.27-248.el7.x86_64.rpm
├── perl-Socket-2.010-4.el7.x86_64.rpm
├── perl-Storable-2.45-3.el7.x86_64.rpm
├── perl-Text-ParseWords-3.29-4.el7.noarch.rpm
├── perl-threads-1.87-4.el7.x86_64.rpm
├── perl-threads-shared-1.43-6.el7.x86_64.rpm
├── perl-Time-HiRes-1.9725-3.el7.x86_64.rpm
└── perl-Time-Local-1.2300-2.el7.noarch.rpm
4. 安裝
rpm -ivh *.rpm 即可
可能還需要 update 如下：
rpm -Uvh update/*.rpm
5. 類似的命令
yumdownloader --resolve --destdir=/root/mypackages/ perl