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Default fg color (SGR 39)
ESC [ 39 mSGR 39 resets the foreground color to the terminal's default, without affecting other attributes. The sequence is
ESC [ 39 m. This is more targeted than SGR 0, which resets all attributes. Useful when you want to clear a color change while preserving bold, underline, or other active attributes.How this is tested: Send
\x1b[31mX\x1b[39mY, verify the second cell's foreground is reset to default (null).Analysis2026-03-26
Supported by all 8 tested terminals — universal adoption. Part of the Core TUI baseline.
Supported by 13 of 13 backends (100%)
Terminal Applications
| Terminal | Version | Support | Notes |
|---|---|---|---|
| iTerm2 | 3.6.9 | ✓ yes | |
| Ghostty | 1.3.1 | ✓ yes | |
| VS Code | 1.112.0 | ✓ yes | |
| Warp | 0.2026.03.18.08.24.03 | ✓ yes | |
| Cursor | 2.6.21 | ✓ yes | |
| tmux | 3.6a | ✓ yes | |
| Kitty | 0.46.2 | ✓ yes | |
| Terminal.app | 2.15 | ✓ yes | |
| GNU Screen | 5.0.1 | ✓ yes |