If you have been using the shell extensively, you would have noticed that at times you will need to have access to more than one terminal at once. If you are using a graphical terminal emulator like Konsole, you might use multiple tabs to achieve this.
However, what to do when you want a solution without using a graphical terminal emulator? Or you are logged into a remote machine and want multiple shells? In the latter case, opening multiple ssh connections will basically waste network bandwidth and even slow down things. We will see how to achieve multiple shells while avoiding these problems.