Ctrl + Shift + Up or Ctrl + Shift + Down to go up/down by line.
How do you scroll through a file in Unix?
On modern Linux systems you can use the [UpArrow] and [DownArrow] keys to scroll through the display. You can also use these keys to move through the output: [Space] – scrolls the display, one screenful of data at a time. [Enter] – scrolls the display one line.
How do I scroll with screen?
Scroll Up in Screen
Inside a screen session, press the Ctrl + A then Esc to enter a copy mode. In the copy mode, you should be able to move your cursor around using the Up/Down arrow keys ( ↑ and ↓ ) as well as Ctrl + F (page forward) and Ctrl + B (page back).