Linux--install network and system command on first OS

http://www.binarytides.com/linux-commands-monitor-network/

1)yum install vnstat
yum install nload -y
type --nload    


2)iftop
iftop -n
yum install iftop -y

3. iptraf

Iptraf is an interactive and colorful IP Lan monitor. It shows individual connections and the amount of data flowing between the hosts. Here is a screenshot


iptraf

yum install iptraf
fedora or centos (with epel)

yum install iptraf-ng -y