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Total line count
Tests whether the terminal can report the total number of lines in the buffer (visible + scrollback). This is used by testing frameworks and terminal introspection tools to verify scrollback behavior.
Scrollback size is not standardized by ECMA-48, DEC manuals, or terminfo. This probe exists for terminal testing and introspection: a harness needs to know whether output entered scrollback and how much history exists. Real terminal emulators expose this information inconsistently, so Termless treats it as a backend capability rather than a portable app feature.
How this is testedautomated
Write 30 lines, verify total line count is at least 30.
Write 30 lines, verify total line count is at least 30.
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.
Analysis2026-05-17
Supported by all 12 tested terminals — universal adoption. Part of the Core TUI baseline.
Supported by 14 of 14 backends (100%)
Terminal Applications
| Terminal | Version | Support | Notes |
|---|---|---|---|
| iTerm2 | 3.6.9 | ✓ yes | Content written to scrollback |
| Ghostty | 1.3.1 | ✓ yes | Content written to scrollback |
| VS Code | ✓ yes | ||
| Warp | ✓ yes | ||
| Kitty | 0.46.2 | ✓ yes | Content written to scrollback |
| Cursor | ✓ yes | ||
| Terminal.app | ✓ yes |