# Cursor Up (CUU)
> Move the cursor up n lines.
- **Sequence:** `CSI Pn A`
- **Defaults:** Pn = 1
- **ECMA-48:** [§8.3.22 CUU – Cursor Up, p. 37](https://archive.org/details/ecma-48-5th-edition-june-1991/page/n50/mode/1up)
- **DEC STD 070:** [§5.4.4 Cursor Up, p. 5-41](https://archive.org/details/bitsavers_decstandar0VideoSystemsReferenceManualDec91_74264381/page/n295/mode/1up)
- **VT220:** [§4.7 Cursor Positioning](https://vt100.net/docs/vt220-rm/chapter4.html#S4.7)
- **VT510:** [CUU—Cursor Up](https://vt100.net/docs/vt510-rm/CUU.html)
Move the cursor `Pn` lines up, keeping its column. A `0` is taken as `1`.
The cursor stops at the top margin if it started at or below it. A cursor
already above the top margin, which only absolute positioning can put there,
stops at the first line instead. CUU never scrolls: at the top margin it
simply goes no further, where [RI](https://control-codes.page/esc/ri/index.html.md) would scroll the region down.
Moving the cursor cancels any pending wrap. DEC STD 070 calls the pending
wrap the *Last Column Flag*, and its appendix on autowrap lists this among
the controls that should reset it
([§D.6.1, p. D-13](https://archive.org/details/bitsavers_decstandar0VideoSystemsReferenceManualDec91_74264381/page/n1199/mode/1up)); xterm clears it in
[`CursorUp`](https://github.com/ThomasDickey/xterm-snapshots/blob/xterm-411a/cursor.c#L271-L284), and libghostty-vt does the same.
[CUD](https://control-codes.page/csi/cud/index.html.md) goes the other way, and [CPL](https://control-codes.page/csi/cpl/index.html.md) moves up and
returns to the left margin as well.
## Validation
### CUU-1: Up one line
Input, one step per line:
```text
\e[3;2H
\e[A
X
```
Expected screen:
```text
|_____|
|_X___|
|_____|
```
### CUU-2: Up n lines, stopping at the first line
Input, one step per line:
```text
\e[3;2H
\e[9A
X
```
Expected screen:
```text
|_X___|
|_____|
|_____|
```
### CUU-3: Stops at the top margin
Input, one step per line:
```text
\e[2;4r # region is lines 2 to 4
\e[3;1H
\e[9A
X
```
Expected screen:
```text
|_____|
|X____|
|_____|
|_____|
```
### CUU-4: Above the top margin
Input, one step per line:
```text
\e[3;4r # region is lines 3 and 4
\e[2;1H # above it
\e[9A
X
```
Expected screen:
```text
|X____|
|_____|
|_____|
|_____|
```
### CUU-5: From a pending wrap
Input, one step per line:
```text
\e[2;1H
ABCDE # fills the line; a wrap is pending
\e[A
X
```
Expected screen:
```text
|____X|
|ABCDE|
|_____|
```
---
This is the Markdown version of . On that page every validation case runs live in libghostty-vt, the terminal emulation core of Ghostty, compiled to WebAssembly.
The validation cases are written in the notation described in .