ANSI Terminal Color Code Generator

An ANSI escape sequence is a special string that starts with the ESC control character (0x1B) and is recognized by terminal emulators as a command rather than printable text. The most common form is the Control Sequence Introducer (CSI), written as ESC followed by an open bracket, which is used to move the cursor, clear parts of the screen, and most relevantly here, change text colors and styles through Select Graphic Rendition (SGR) parameters.

SGR stands for Select Graphic Rendition. It is the subset of ANSI CSI sequences that ends with the letter m and carries one or more numeric parameters that control display attributes such as foreground color, background color, boldness, italics, underline, and blink. SGR codes were standardized in ECMA-48 and ISO/IEC 6429.

Terminals evolved over time. The original VT100 family supported only eight colors plus eight bright variants, which became the 16-color SGR range (30 to 37, 90 to 97 for foreground). xterm later introduced an indexed 256-color palette accessed with 38;5;N. Modern terminals can address any RGB color using 38;2;R;G;B, often called true-color or 24-bit color. Each mode trades capability for backward compatibility.

The reset sequence, written as ESC [ 0 m, clears every previously set SGR attribute and returns the terminal to its default foreground color, default background color, and default text styles. Without a trailing reset, the chosen color or style would continue to apply to whatever text the program prints next, which is rarely desired.

Blinking text (SGR code 5) is technically part of the standard, but most modern terminal emulators either render it as bold, render it without animation, or ignore it entirely. The behaviour depends on the emulator and on user accessibility preferences, since flashing text can trigger discomfort or seizures. Tools that need to attract attention typically rely on reverse video or bright colors instead.