Screen Commands

In normal terminal

Command	Description
screen -S <sessionname>	Start a new screen session with a given name and attach to it.
screen -ls	Lists all existing screen sessions.
screen -r	Reattach this terminal to the only existing screen session.
screen -r -S <sessionname>	Reattach this terminal to an existing screen session by name.
screen -S <oldname> -X <newname>	Rename a screen session.
screen -S <sessionname> -X quit	Kill the specified screen session by executing quit.

Within a screen session

Prepend every command with ctrl + A

Command	Description
Ctrl+A - ?	Show help
Ctrl+A - d	Detach the current screen session from this terminal. The screen session and its processes remain in existence.
Ctrl+A - c	Create a new window and switch to it.
Ctrl+A - k (y)	Kill the current window.
Ctrl+A - p	Go to the previous screen.
Ctrl+A - n	Go to the next screen.
Ctrl+A - <number>	Go to a specific screen number.
Ctrl+A - "	Go to the screen selection page. Select a screen from the list using the arrow keys.
Ctrl+A - S	Split the current window in half horizontally.
Ctrl+A - |	Split the current window in half vertically.
Ctrl+A - Tab	Cycle through window regions.
Ctrl+A - X	Eliminate a window split.

See if you are inside a screen

echo $TERM

normal ssh session:

$ echo $TERM
xterm-256color

inside screen:

$ echo $TERM
screen.xterm-256color

scrolling in screen:

Ctrl+A - [

Press ESC to resume normal operation

enable normal scrolling:

Using the scrollwheel in GNU screenStack Overflow