Screen is a program that acts as a terminal multiplexer. That means you will be able to

resume your command line session on another computer even if it was disconnected
share your keyboard actions with another person on another computer
log your session to a file

Using Screen

To start a new screen, open a console and enter:

screen

If you loose your connection, you can resume your screen by calling

screen -r

If you want to share a screen session with another user, let him log in as your user and call

screen -x

After calling screen,

Control-a, Control-c creates a new terminal screen

Control-a, " shows a list of terminal screens

Control-a, n switch to the next screen

Control-a, p switch to the previous screen

Control-a, a switches to the most-recently-used screen

Control-a, d kills the actual shell

Control-a, c creates a new shell

Control-a, H logs your session to a plain-text file

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