Screen is some sort of session manager for the Linux console. You can maintain multiple sessions with Screen, and easily switch between them. It also protects your shell activities from disconnection, since the session doesn't stop at disconnecting.

You need Screen to do all this stuff. This is how you install it:

sudo apt-get install screen

After that you can use Screen. Start it with the following command:

screen

After Screen is started you can use it by creating an extra screen by hitting ctrl+A and ctrl+C quickly after each other. To switch between the created screens hit ctrl+A [spatie] after each other.

To reconnect a Screen when you're coming back you can use the following command:

screen -r

To use an existing Screen for your current session you can use the following:

screen -D -r