Use screen when you want to manage multiple sessions in a terminal. Install it on Ubuntu

sudo apt-get install screen

There are a lot of options for screen. I won't go into them. I use screen most often when I shell into a remote server and want to hop into my database, or parse a log file, run top and need to run another process at the same time. Instead of opening another terminal session, I just use screen and bypass login/sudo or whatever other options I have configured for my current terminal session.

Start up screen:

screen

Create a new screen session

ctl+a+c

Tab between your screen sessions:

ctl+a+n

There is a whole lot more to screen, like assignment of sessions to other users and groups.