ifconfig

syntax: ifconfig [interface] option
Examples:
ifconfig eth0 192.168.1.50
ifconfig eth0 down
ifconfig eth0 up

ifconfig is used to configure the kernel-resident network interfaces.
ifconfig with no argument/option, displays the status of the currently active interfaces.

ifconfig -a #Displays status of all NICs

ifconfig is obsolete in RHEL6, replaced by:
ip addr
or
ip link

For statistics use:
ip -s link