DL — Delete Line (CSI Pn M)

Used in

Real-world tools that emit this sequence — anchors the bytes to commands you've already used.

• vim, neovim — `dd` (delete line) primitive—every `dd` / `d<motion>` that removes whole lines compiles down to `\x1b[<N>M` at the start row inside the DECSTBM region — the lines below visibly pull up without the editor having to repaint each remaining row
• less, more — scroll-down past top line—every forward-scroll step emits `\x1b[<N>M` at row 1 to slide the top N lines off-screen; new tail lines are then written into the blanks IL/DL leaves at the bottom of the page region
• ncurses — `deleteln()` / `wdeleteln()`—libncurses' `deleteln(WIN)` lowers directly onto `dl1` / `dl` terminfo caps — any program that scrolls a region by repeatedly emitting `dl` (top, irssi, tmux's own status pop-up) re-uses DL via this API rather than touching the bytes
• tmux status-line redraw, copy-mode prompt clear—tmux's bottom status line and copy-mode prompt are drawn inside a 1-row DECSTBM region — clearing them is a single `\x1b[1M` instead of a full-row repaint, which keeps redraws under 1 ms even at 240 Hz refresh
• irssi, weechat, glirc — IRC backscroll trimming—when an IRC backlog hits the visible cap, the TUI emits `\x1b[<N>M` at the chat region's top row to drop the oldest N lines — fresher messages then write into the blanks DL leaves at the bottom, no global repaint

Related pitfalls

Known footguns this sequence creates in the wild. Each links to the full symptom + cause + fix.

• ⚠DL inside a decstbm scroll region pulls subsequent lines up — content above the region stays untouched, no bottom-line backfill·#alt-screen-newline
• ⚠\x1b[M (omitted Pn) defaults to 1 — also collides visually with \x1bM (RI, reverse-index, no CSI introducer)·#csi-default-params

Frequently asked

Short answers to the questions developers actually search for this sequence.

What's the difference between \x1b[M (DL) and \x1b[K (EL)?

DL (\x1b[Pn M) deletes Pn whole rows starting at the cursor — subsequent rows shift up to fill the gap, and blank rows appear at the bottom of the scroll region. EL (\x1b[Pn K) erases characters *within the current row* — \x1b[0K clears from cursor to end-of-line, \x1b[1K from start to cursor, \x1b[2K the whole row. EL leaves the row in place (still visible, just blank); DL removes the row entirely and the following rows scroll up. Use EL to repaint a status line; use DL to drop a completed log entry.

Does \x1b[M move the cursor?

No. After DL the cursor stays on the same row (and at the same column) — what changed is the *content* of that row, which now holds whatever was on the row immediately below before the operation. ECMA-48 §8.3.32 specifies cursor position is unchanged. Watch the visual confusion: DL deletes the row at the cursor, but because the rows below scroll up, it *looks* like the cursor moved down to consume the next row. Mentally model DL as 'delete this row, everything below comes up by one' — not 'the cursor advances'.