DECSET 7 — DECAWM (autowrap mode)

CSI ? 7 h (DECAWM set, the usual default) enables autowrap: writing a character in the last column moves the cursor to the start of the next line (with the 'pending wrap' deferred-wrap behavior). CSI ? 7 l disables autowrap, so characters at the right margin overwrite the last cell in place.

frame

DEC-private-mode introducer: \x1b[? ESC [ ? (0x1B 0x5B 0x3F)

terminator (none): ST · BEL

parameters / subcommands

id	name	bytes (ST)	meaning
set	Enable (DECSET)	\x1b[?7h	CSI ? 7 h enables autowrap: a glyph written in the last column sets a 'pending wrap' so the NEXT glyph appears at column 1 of the following line (the VT deferred-wrap rule).
reset	Disable (DECRST)	\x1b[?7l	CSI ? 7 l disables autowrap: glyphs written at the right margin overwrite the last column and the cursor does not advance past it.

gotchas

The VT 'deferred wrap' / pending-wrap rule means the cursor visually sits in the last column after filling it; the wrap happens when the NEXT printable arrives, not immediately. This trips up cursor-position math.
DECAWM is usually ON by default; programs that draw fixed layouts often turn it OFF (?7l) to avoid accidental wraps, then restore it.
With autowrap off, you cannot write to the very last cell and then move on by printing; you must reposition with CUP.
Wrapping interacts with double-width (CJK) glyphs at the right margin, which may force an early wrap.
Restore the prior autowrap state on exit; leaving ?7l set makes the shell's long lines overwrite themselves.

provenance

source: https://invisible-island.net/xterm/ctlseqs/ctlseqs.html
version: xterm ctlseqs, patch #410, 2026/04/19
retrieved: 2026-05-29 · updated: 2026-05-29T00:00:00Z

per-fact attribution:

#summary — https://invisible-island.net/xterm/ctlseqs/ctlseqs.html xterm ctlseqs: Ps = 7 -> Auto-Wrap Mode (DECAWM). When set, text wraps to the next line at the right margin; when reset, the cursor stays at the right margin and overwrites.
ext.params — https://vt100.net/docs/vt510-rm/DECAWM.html DEC VT510 manual: DECAWM (mode 7) controls whether the cursor wraps to the next line after the rightmost column.