ANSI escape

Learn colors and cursor with ANSI escape sequences.

ANSI escape sequences

ANSI escape sequences are used in terminals for colors, cursor position and style. They all start with ESC (decimal 27, octal \033); then [ and the command. For example \033[31m makes text red, \033[0m resets all formatting.

Color codes: 30 black, 31 red, 32 green, 33 yellow, 34 blue. Cursor movement: \033[H goes to top-left, \033[2J clears the screen. In C you print with printf("\033[31mred\033[0m\n"). In a test environment the ESC character is invisible but the output is deterministic.

Color and reset

The basic method of using color: turn on, write, reset. First turn on the color with \033[31m, write the text, then reset formatting with \033[0m. Otherwise all subsequent output stays colored.

In C you can do this in a single printf: printf("\033[31mred\033[0m\n");. Here \033 produces the ESC character, \n a new line. In a test environment this output contains the ESC character; the expected output uses \u001b for it. The output is deterministic.

Exercise Print colored text

Print text in red with printf("\033[31mred\033[0m\n");. Reset with \033[0m after the color code.

Show example solution

#include <stdio.h>

int main(void) {
    printf("\033[31mred\033[0m\n");
    return 0;
}

Test yourself

Which ANSI code gives red color?
- 30
- 31
- 33
- 32
Show answer

31 — 31 is the code for red color.
Match ANSI codes

\033[31m

Red
\033[0m

Reset
\033[2J

Clear screen
\033[H

Top-left

Red color

printf("\033[____mred\033[0m
");

Show answer

printf("\033[31mred\033[0m
");

Next lesson: Terminal size

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