ANSI

Style your terminal with ANSI magic ✨

ANSI escape codes are sequences of characters used to control the style, color, and behavior of text output in a terminal. They are widely supported across Unix terminals, macOS Terminal, modern Windows consoles (10+), and many terminal emulators like VS Code, iTerm2, Alacritty, etc.

What is an ANSI Escape Code?

An ANSI escape code starts with the escape character followed by a Control Sequence Introducer (CSI), then one or more codes (parameters), and ends with a command character.

Syntax

ESC [ parameters m

• ESC is the escape character (ASCII 27 or \x1b)
• [ is the Control Sequence Introducer (CSI)
• parameters are semicolon-separated values (e.g., 1;31)
• m indicates text formatting (SGR - Select Graphic Rendition)

This is used for text formatting. For example:

echo -e "\033[1;32mBold Green Text\033[0m"

Outputs Hello in red, then resets.

Escape Character ESC

All ANSI sequences begin with the escape character (byte 27 in decimal).

Representation	Description
\x1b	Hex notation (common in JS)
\033	Octal notation (common in Bash)
\u001b	Unicode notation (JSON-safe)
\e	Shorthand in Bash/Zsh

Style Codes (SGR - Select Graphic Rendition)

SGR parameters define text style, color, and effects.

Text Attributes

Code	Style
0	Reset all
1	Bold
2	Dim
3	Italic
4	Underline
5	Blink (slow)
6	Blink (fast)
7	Reverse (invert fg/bg)
8	Hidden
9	Strikethrough

Reset Variants:

Code	Resets
21	Bold/Double Underline
22	Bold + Dim
23	Italic
24	Underline
25	Blink
27	Inverse
28	Conceal
29	Strikethrough

Color Codes

Standard Colors (4-bit)

Foreground (Text)

Code	Color	Bright Code	Bright Color
30	Black	90	Bright Black (Gray)
31	Red	91	Bright Red
32	Green	92	Bright Green
33	Yellow	93	Bright Yellow
34	Blue	94	Bright Blue
35	Magenta	95	Bright Magenta
36	Cyan	96	Bright Cyan
37	White	97	Bright White

Background Colors

Code	Color	Bright Code	Bright Color
40	Black	100	Bright Black
41	Red	101	Bright Red
42	Green	102	Bright Green
43	Yellow	103	Bright Yellow
44	Blue	104	Bright Blue
45	Magenta	105	Bright Magenta
46	Cyan	106	Bright Cyan
47	White	107	Bright White

Extended Colors

256-Color Mode

Format:

• Foreground: \033[38;5;<n>m
• Background: \033[48;5;<n>m

Where <n> is from 0 to 255.

Color Breakdown

Range	Meaning
0–15	Standard + Bright colors
16–231	6×6×6 RGB cube
232–255	Grayscale ramp (24 steps)

RGB Cube (16–231)

Each RGB channel (r, g, b) can be from 0–5 (6 levels).

Formula:

code = 16 + (36 × r) + (6 × g) + b

Example:

echo -e "\033[38;5;196mBright Red\033[0m"

Grayscale Ramp (232–255)

24 shades from near black to white, no color hue.

for i in {232..255}; do
  echo -ne "\033[48;5;${i}m \033[0m"
done

True Color (24-bit)

Format:

• Foreground: \033[38;2;<r>;<g>;<b>m
• Background: \033[48;2;<r>;<g>;<b>m

Where r, g, and b are 0–255.

Examples

echo -e "\033[38;2;255;140;0mOrange\033[0m"
echo -e "\033[48;2;0;0;64;38;2;255;255;255m White on Navy \033[0m"

Gradient Example

for i in {0..255..25}; do
  echo -ne "\033[48;2;${i};0;255m ${i} \033[0m"
done

Combining Multiple Codes

You can combine multiple SGR parameters with semicolons:

ESC="\033"

echo -e "${ESC}[1;4;31mBold Underlined Red${ESC}[0m"

Cross-Platform Support

ANSI codes are supported on:

• Unix (Linux, macOS)

• Windows 10+ (older versions require ANSICON or enabling VT)

• Node.js (supports ANSI natively)

• Browsers (via dev tools console with limited support)

• Many programming languages:

  • Python: print("\033[31mRed\033[0m")
  • Bash: echo -e "\033[32mGreen\033[0m"
  • JavaScript: console.log("\x1b[36mCyan\x1b[0m")

Utilities

Reset Code

Always end ANSI sequences with reset to avoid carryover:

RESET = "\x1b[0m";

JavaScript

const style = (...codes: number[]) => `\x1b[${codes.join(";")}m`;

console.log(`${style(1, 34)}Bold Blue${style(0)}`);

Bash Function

color() { echo -e "\033[$1m$2\033[0m"; }
color "1;33" "Bold Yellow Text"

Cursor Control (Bonus)

Code	Function
\x1b[H	Move to home position
\x1b[2J	Clear screen
\x1b[K	Clear line to right
\x1b[<n>A	Move cursor up
\x1b[<n>B	Move cursor down
\x1b[<n>C	Move cursor forward
\x1b[<n>D	Move cursor backward

References

• Wikipedia – ANSI escape code
• Xterm 256-color chart
• 256 colors cheat sheet