Using Linux screen in Ubuntu

Screen is useful when updating system, usually takes long time, whenever accidentally disconnected, you can reconnect again.

Install
apt-get install screen

Start screen
$screen

Reattach
$screen -r

Control command
ctrl-a

Next Screen
ctrl-a n

Prev Screen
ctrl-a p

Detach Screen
ctrl-a d

New Screen
ctrl-a c

Quit
ctrl-a \

Help keys
ctrl-a ?

Source: http://www.rackaid.com/blog/linux-screen-tutorial-and-how-to/