CentOS yum repository setting

# cat /etc/yum.repos.d/centos.repo
[centosbase]
name=CentOS
baseurl=http://mirror.centos.org/centos/6/os/$basearch/
gpgcheck=0
enabled=1
--
# yum search nmap

# yum install nmap -y

====
DVD as CentOS repo

# mkdir /mnt/cdrom
# mount -t iso9660 /dev/cdrom /mntcdrom

# cat /etc/yum/repos.d/mydvd.repo
[centosdvd]
name=CentOS7DVD
baseurl=file:///mnt//cdrom/
gpgcheck=0
enabled=1

# yum search locate
# yum install mlocate

===
Redhat/Centos Install EPEL Repository
Eg: for package nmon tool

# wget https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm

# yum install ./epel-release-latest-7.noarch.rpm

# yum repolist

# yum search nmon

# yum install nmon -y

===
Install Gnome GUI desktop
# yum -y groups install "GNOME Desktop"
# reboot or startx