How to scroll up and down in sliced "screen" terminal
Solution 1:
1.Control+a, then Escape.
2. after that, you should be able to move your cursor around using the arrow keys:
↑, ↓, PgUp, PgDn
3. return control: q or Esc
Solution 2:
Press Ctrl-a then [ will enter the copy mode, and you can scroll up and down like vim editor. Leave the copy mode by pressing Escape.