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HPA horizontal position absolute (CSI `)
CSI Ps `HPA (Horizontal Position Absolute) moves the cursor to an absolute column on the current row. The sequence is
CSI Ps ` where Ps is the 1-based column number (default 1). HPA is functionally equivalent to CHA (CSI G) but uses a different final character. Both are defined in ECMA-48 — some older terminals only implement one of the two.How this is testedautomated
Write "ABCDEFGH" then send
Write "ABCDEFGH" then send
\x1b[5` (HPA col 5), verify cursor column is 4 (0-based).The same probe runs against headless backends (via Termless) and real terminal apps (via a daemon launched in each terminal). This lets us distinguish parser correctness from rendering correctness.
Analysis2026-04-06
Supported by 11 of 14 backends (79%)
Terminal Applications
| Terminal | Version | Support | Notes |
|---|---|---|---|
| iTerm2 | 3.6.9 | ✓ yes | |
| Ghostty | 1.3.1 | ✓ yes | |
| VS Code | ✓ yes | ||
| Warp | ✓ yes | ||
| Cursor | ✓ yes | ||
| Terminal.app | ✓ yes |
Headless Backends
Parser correctness only — a ✓ means the parser accepts the sequence.
| Backend | Version | Support | Notes |
|---|---|---|---|
| Alacritty | 0.26.0 | ✓ yes | |
| Kitty | 0.40.0 | ✓ yes | |
| WezTerm | 0.1.0-fork.5 | ✓ yes | |
| xterm.js | 5.5.0 | ✓ yes | |
| vt100.js | 0.2.1 | ✗ no | HPA (horizontal position absolute) not implemented in vt100.js baseline emulator |
| vterm | 0.2.0 | ✗ no | HPA (horizontal position absolute) not implemented in vterm.js |