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DECALN screen alignment (ESC # 8)
ESC # 8DECALN (DEC Screen Alignment Test) fills the entire screen with the letter 'E'. The sequence is
ESC # 8. Originally designed for service technicians to verify screen alignment on CRT displays, it is now primarily used as a quick way to fill the screen with known content for testing purposes. DECALN also resets scroll margins and moves the cursor to the home position (row 1, column 1).How this is tested: Send
\x1b#8 (DECALN), verify cell at (0,0) contains 'E'.Supported by 3 of 14 backends (21%)
Terminal Applications
| Terminal | Version | Support | Notes |
|---|---|---|---|
| iTerm2 | 3.6.9 | ? unknown | |
| Ghostty | 1.3.1 | ? unknown | |
| Kitty | 0.46.2 | ? unknown | |
| VS Code | 1.113.0 | ? unknown | |
| Warp | 0.2026.03.18.08.24.03 | ? unknown | |
| Cursor | 2.6.21 | ? unknown | |
| Terminal.app | 2.15 | ? unknown |