VPA — Vertical line position absolute (CSI d)

Used in

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

• vim / neovim status line redraw—`:redrawstatus` and the per-window `&statusline` rebuild path use VPA to jump to the status row while preserving the column the cursor was sitting in — avoids a CUP `\x1b[<row>;<col>H` round-trip and the extra column-math when the buffer cursor is mid-line
• htop / btop / glances column-aligned rows—after writing the leftmost column of header / footer text, htop emits VPA to step down to the next row at the same column instead of recomputing the column for every row — the column constancy is the whole reason htop's vertical bars render cleanly under SIGWINCH redraws
• ncurses `wmove(WIN, row, col)` when column unchanged—ncurses's diff renderer emits VPA `\x1b[<row>d` instead of CUP when its dirty-line tracker indicates the column matches the previous cursor column — a 1-2 byte saving per redraw that adds up on slow remote PTYs
• less status-line repaint—less repaints its `:` prompt by VPA to the bottom row + EL `\x1b[K` (clear) + write — the column was 0 from the previous newline so VPA suffices without a CUP
• tmux pane-status-format updates—tmux's per-pane status line update (`set -g pane-status-format`) emits VPA to land on the status row inside the pane viewport — `\x1b[<row>d` survives the per-pane translation cleanly even when panes are split horizontally and column origin differs

Related pitfalls

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

• ⚠\x1b[0d (VPA, Pn=0) does not land on row 0 — VPA is 1-based like CUP, row 1 is \x1b[1d·#cup-1-based-not-0-based
• ⚠\x1b[d (omitted Pn) defaults to 1, not 0 — \x1b[d ≡ \x1b[1d, jumps to the first row·#csi-default-params

Frequently asked

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

How does \x1b[<n>d (VPA) differ from \x1b[<n>;<col>H (CUP)?

VPA (\x1b[Pn d) sets the cursor to row Pn *while preserving the current column*. CUP (\x1b[Pn1;Pn2 H) sets both row and column. Use VPA when you're walking down a column to draw a vertical sidebar / scrollbar / column-aligned status indicator without recomputing the column each row. Both row indices are 1-based per ECMA-48; \x1b[1d lands at the top row. If you need to clamp at the screen edge, the terminal handles it for you (most clamp to row 1 / row LINES).

Is \x1b[<n>d (VPA) 0-based or 1-based?

1-based, same as CUP. \x1b[1d is the top row; \x1b[0d is *not* the top row — Pn=0 is treated as Pn=1 per ECMA-48 (most terminals silently clamp; some legacy parsers reject the clause). Omitting Pn also defaults to 1: \x1b[d ≡ \x1b[1d. See pitfall cup-1-based-not-0-based for the same trap on CUP / HVP / CHA.