Install package from DVD ISO (not Internet)
// Kiem tra DVD o trang thai ket noi (CONNECT)
1.# ll /dev/cdrom
2.#mkdir /mnt/cdrom
3.#mount /dev/cdrom /mnt/cdrom
---->mount: /dev/sr0 is write-protected, mounting read only !!!
4.#nano /etc/yum.repos.d/CentOS6.repo --->add noi dung
[CentOS6]
name=CentOS6
baseurl=file:///mnt/cdrom
enabled=1
gpgcheck=0 
gpgkey=file:///etc/pki/rpm-gpg/RMP-GPG-KEY-CentOS-6

Ghi chu: co the xac dinh bang lenh # ll /etc/pki/rpm-gpg ---ENTER
  Ctrl+X ---Y ---Enter to SAVE FILE
5#yum repolist --->xuat hien gia tri repolist khac 0 là OK
6#yum --disablerepo=*  --enablerepo CentOS6 install <package_name>

ex: #yum --disablerepo=* --enablerepo CentOS6 install mc