CSI IL / DL — Insert / Delete Line

IL (final 'L') inserts Pn blank lines at the cursor row, scrolling lines below downward within the scroll region; DL (final 'M') deletes Pn lines at the cursor row, scrolling lines below upward. Both default Pn to 1 and operate only within the current scroll region (DECSTBM).

frame

CSI introducer: \x1b[ ESC [ (0x1B 0x5B)

terminator (none): ST · BEL

parameters / subcommands

id	name	bytes (ST)	meaning
il	IL — Insert Line (L)	\x1b[2L	CSI Pn L inserts Pn blank lines at the cursor row; existing lines from the cursor down scroll downward within the scroll region. Blank lines take the current background color.
dl	DL — Delete Line (M)	\x1b[2M	CSI Pn M deletes Pn lines starting at the cursor row; lines below scroll upward and blank lines appear at the bottom of the scroll region.

gotchas

IL/DL operate within the current scroll region (DECSTBM); lines outside the region are not affected and do not move.
DL's final byte 'M' (0x4D) is unrelated to the mouse-report 'CSI M'; context (parameters/prefix) disambiguates.
Inserted/blank lines are filled with the current SGR background color.
If the cursor is outside the vertical scroll region, IL/DL have no effect.
Pn of 0 is treated as 1.

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: CSI Ps L = Insert Ps Lines (IL); CSI Ps M = Delete Ps Lines (DL). Default Ps = 1.
ext.params — https://ecma-international.org/publications-and-standards/standards/ecma-48/ ECMA-48 defines IL (final 'L') and DL (final 'M') operating within the scroll region, default Pn 1.

agent: curl -H 'accept: application/json' wire.phall.io/terminal-csi/il or /terminal-csi/il.json

CSI IL / DL — Insert / Delete Line

frame

parameters / subcommands

gotchas

provenance

see also