In this tutorial we will learn simple steps to configure the static ip address in Ubuntu by using command line.
It is always be a good practice to work on Linux or Unix system using command line.As a system admin we always prefer to work by using command line.

Follow the given below steps to configure static ip address through command line in Ubuntu

Step 1: Login into your system and become a superuser or root

sudo su - 

or 

su -

Step 2: Now edit the file /etc/network/interfaces. Before this first of all you have to check what is the ethernet device name which is available in system and on which we will configure the static ip address.

First of all run the below command and find the ethernet device name,here for eg, we are using eth0

ifconfig -a 

Now edit the /etc/network/interfaces file using your favorite file editor and paste the given below content as per your information. (Here I am using the vi editor)

Replace the given value

aa.bb.cc.dd replace with the ip address assigned for the system
yyy.yyy.yyy.yyy replace with Netmask of IP Address
pp.qq.rr.ss replace with Gateway IP Address

vi /etc/network/interfaces

auto eth0
iface eth0 inet static
address aa.bb.cc.dd
netmask yyy.yyy.yyy.yyy
gateway pp.qq.rr.ss

For eg.

auto eth0
iface eth0 inet static
address 192.168.122.101
netmask 255.255.255.0
gateway  192.168.122.101

Step 3: Now restart the network service

/etc/init.d/networking restart

Step 4: To change the Nameserver settings. Edit the resolv.conf file. In below example I am using Google Nameserver IP Address. You can replace the nameserver information as per your network requirement.

vi /etc/resolv.conf

nameserver 8.8.8.8
nameserver 8.8.4.4