scrollUp

Scrolls the active scroll region up by one line (SU, CSI 1 S).

Only cells within the active horizontal margins move. A full-width region starting at the top of the viewport may admit its top line to scrollback; partial-width scrolling never does. The cursor position is preserved.

Scrolls the active region up by count lines, capped at its height. Non-positive counts are ignored. Preserves the cursor position and uses the same horizontal-margin and history-admission rules as scrollUp. Work is bounded by the grid dimensions, not the supplied count.