SGR 40–47 — Background color (8 basic)

Byte forms

Every common string-literal form so you can paste-and-search either direction.

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Description

The 8 basic background colors mirror 30–37 at parameters 40–47: 40 black, 41 red, 42 green, 43 yellow, 44 blue, 45 magenta, 46 cyan, 47 white. SGR 49 returns the background to the terminal default — the surgical complement to a full \x1b[0m reset. ECMA-48 §8.3.117 specifies the range; every terminal in the support matrix above honours the full surface, including the Linux console (8-colour mode) and ConPTY. Like the foreground, the rendered RGB depends entirely on the terminal colour scheme — there is no canonical 'ANSI red bg' — and the user's theme can remap any of the 8 slots arbitrarily. The bright background variants live at SGR 100–107 (aixterm extension, see sgr-bg-bright); for indexed 256-colour backgrounds use \x1b[48;5;Nm, for 24-bit RGB use \x1b[48;2;R;G;Bm. Combine basic bg with basic fg in one sequence by chaining parameters: \x1b[31;47m is red-on-white (semicolons are separators, not a sequence ender).

Two background-specific traps land more often than fg ones. (1) Background colour pads cells: when you don't reset the bg before emitting a newline, the bg fill carries to the end of the line on most terminals — your 'red label' turns into a long red bar past the text. Always emit \x1b[49m (bg-off) or \x1b[0m before \n. (2) Naïve width math breaks alignment when you add colour: printf '%-20s' and len(string) count the 4–7 SGR bytes that don't print, so coloured cells look shorter than uncoloured ones. The fix is to strip ANSI first and measure visible width separately — TUI libraries (rich, blessed, lipgloss, ratatui) handle this for you, but raw printf does not. And as with all colour output: gate emission on isatty(stdout) and honour NO_COLOR=1; without those, scripts that look fine on dev leak SGR bytes into log files and CI captures (see no-color). On the Linux console / fbcon the basic 16-bg surface is the only background that renders — \x1b[48;5;Nm and \x1b[48;2;R;G;Bm silently quantize to the nearest of those slots.

Disable background surgically with \x1b[49m — leaves foreground and attributes intact. The pair \x1b[41m…\x1b[49m is the right shape; reaching for \x1b[0m clobbers more than you intended. For finer control beyond the 8 slots see sgr-bg-256 (256-colour palette) or sgr-bg-truecolor (24-bit RGB) — both inherit the same 'reset before newline' gotcha. For the matching foreground side see sgr-fg-basic; for the bright background variants that aixterm-style terminals also expose see sgr-bg-bright. If you want a textual reset that also clears every other SGR attribute you set in the same span, sgr-reset (\x1b[0m) is the broad close.

Spec citation: ECMA-48 §8.3.117 (SGR parameters 40–47, 49)

Examples

for c in 40 41 42 43 44 45 46 47; do printf "\033[${c}m  \033[0m"; done; echo

for c in range(40, 48): print(f'\x1b[{c}m  \x1b[0m', end='')

for c := 40; c <= 47; c++ { fmt.Printf("\x1b[%dm  \x1b[0m", c) }

for (let c = 40; c <= 47; c++) process.stdout.write(`\x1b[${c}m  \x1b[0m`)

for (int c = 40; c <= 47; c++) printf("\x1b[%dm  \x1b[0m", c);

Terminal support

xterm

yes

Linux console (fbcon)

yes

macOS Terminal.app

yes

iTerm2

yes

Windows Terminal

yes

cmd.exe / ConPTY

yes

kitty

yes

alacritty

yes

WezTerm

yes

Ghostty

yes

GNOME Terminal

yes

Konsole

yes

tmux

yes

GNU screen

yes

Related sequences

• SGR 30–37 — Foreground color (8 basic)
• SGR 100–107 — Bright background color
• SGR 48;5;n — 256-color background

In the family cookbook

↗SGR cookbook · 2. 16-color basic — `\x1b[31m` and friends