Features›Text›Reverse Index at Scroll Top

Reverse Index at Scroll Top

Category: text · Baseline: core · Tags: VT100 · Specification ↗

RI (ESC M) at the top of the scroll region scrolls the entire region down, inserting a blank line at the top. This is the inverse of a newline at the bottom of the scroll region. Used for smooth scrolling and status line implementations.

How this is testedautomated
Set scroll region, write text at top row, send Reverse Index (ESC M), verify content shifted down by one line.

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 all 12 tested terminals — universal adoption. Part of the Core TUI baseline.

Supported by 13 of 14 backends (93%)

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
vt100.js	0.2.1	✓ yes
vterm	0.2.0	✓ yes
WezTerm	0.1.0-fork.5	✓ yes
xterm.js	5.5.0	✓ yes

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