rainbow.sh RawHistoryFolder

1#!/bin/sh
2# 60 fps animation: a scrolling rainbow. Each frame ends with a form feed.
3# usage: rainbow.sh [fps] [width]
4fps=${1:-60}
5width=${2:-40}
6exec awk -v fps="$fps" -v w="$width" 'BEGIN {
7	pi = 3.14159265; step = 1.0 / fps; t = 0
8	while (1) {
9		line = ""
10		for (i = 0; i < w; i++) {
11			p = (i * 0.25) - (t * 6)
12			r = int(127 + 127 * sin(p)); g = int(127 + 127 * sin(p + 2 * pi / 3)); b = int(127 + 127 * sin(p + 4 * pi / 3))
13			line = line sprintf("\033[48;2;%d;%d;%dm \033[0m", r, g, b)
14		}
15		printf "%s\f", line
16		fflush()
17		system("sleep " step)
18		t += step
19	}
20}'