Add 24-bit color rainbow script

Author: roosta

rainbow.sh

@@ -0,0 +1,16 @@
+#!/bin/bash
+# Based on: https://gist.github.com/XVilka/8346728
+
+awk -v term_cols="${width:-$(tput cols || echo 80)}" 'BEGIN{
+    s="/\\";
+    for (colnum = 0; colnum<term_cols; colnum++) {
+        r = 255-(colnum*255/term_cols);
+        g = (colnum*510/term_cols);
+        b = (colnum*255/term_cols);
+        if (g>255) g = 510-g;
+        printf "\033[48;2;%d;%d;%dm", r,g,b;
+        printf "\033[38;2;%d;%d;%dm", 255-r,255-g,255-b;
+        printf "%s\033[0m", substr(s,colnum%2+1,1);
+    }
+    printf "\n";
+}'