How do you scroll up the screen?

I am not sure if there is an existing mechanism to screen a screen with multiple lines on display (lets say 20 lines)…
i want to add a new line, and want the screen to shift all existing line up (and line 1 gets pushed out)… there is no need to buffer up the line that got pushed out ?

currently i am thinking of just redraw the screen with content of lines #2-#20 and then add the extra line, but before trying the brute way, want to find out if there are existing elegant method ?