Appearance
Cursor back (CUB)
ESC [ N DCUB moves the cursor back (left) by N columns. The sequence is
ESC [ N D (default N=1). The cursor stops at the left edge of the screen and does not wrap to the previous line.
CUB is one of the small cursor-relative operations that let applications update in place without repainting a full screen. It is heavily used by line editors, prompts, spinners, and progress indicators. The no-wrap behavior is load-bearing: moving left from the first column should clamp, not jump into the previous row.How this is testedautomated
Write "ABC" then send
Write "ABC" then send
\x1b[2D (CUB 2), verify cursor column is 1 (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.
Analysis2026-09-28
Supported by 9 of 14 backends (64%)
Terminal Applications
| Terminal | Version | Support | Notes |
|---|---|---|---|
| iTerm2 | 3.6.9 | ✓ yes | |
| Ghostty | 1.3.1 | ✓ yes | |
| Kitty | 0.46.2 | ✗ no | got 1;7, expected 1;2 |
| VS Code | ✗ no | ||
| Warp | ✗ no | ||
| Cursor | ✗ no | ||
| Terminal.app | ✗ no |