Test 24 bit colors in terminals

24-bit-color.sh

#!/bin/bash

color() {
        echo -en "\e[48;2;$1;$2;$3m "
}

reset() {
        echo -e "\e[m"
}

rainbow() {
        local t=$(( $1 % 43 * 255 / 43 ))
        local q=$(( 255 - t ))
        case $(( $1 / 43 )) in
                0) color 255  $t   0;;
                1) color  $q 255   0;;
                2) color   0 255  $t;;
                3) color   0  $q 255;;
                4) color  $t   0 255;;
                5) color 255   0  $q;;
        esac
}

for i in   {0..127}; do color $i 0 0; done; reset
for i in {255..128}; do color $i 0 0; done; reset

for i in   {0..127}; do color 0 $i 0; done; reset
for i in {255..128}; do color 0 $i 0; done; reset

for i in   {0..127}; do color 0 0 $i; done; reset
for i in {255..128}; do color 0 0 $i; done; reset

for i in   {0..127}; do rainbow $i; done; reset
for i in {255..128}; do rainbow $i; done; reset