OS: rhel 6.0
DIR: /etc/yum.repos.d/server.repo
文件内容：
[base]
name=server rpm
baseurl=http://instructor.example.com/pub/rhel6/dvd/
gpgcheck=0
if baseurl is local dir（单引号双引号均可）
baseurl='file:///media/RHEL_6.0 x86_64 Disc 1'
Gnome only needs 2 packages:
yum groupinstall "X Window System" Desktop