#!/bin/sh
# Print all 256 colors

black="\e[38;5;232m"
white="\e[38;5;255m"

# 16 standard colors -> 0...15

for i in $(seq 0 15); do
  [ $i -lt 8 ] && fg="$white" || fg="$black"
  bg="\e[48;5;${i}m"
  printf '%b%b   %2d    '  "$fg"  "$bg"  "$i"
done
printf '%b\n' '\e[0m'

# 216 colors -> 16...231

for i in $(seq 0 5); do
  for j in $(seq 0 35); do
    n=$(( 16 + 36 * i + j ))
    [ $j -lt 18 ] && fg="$white" || fg="$black"
    bg="\e[48;5;${n}m"
    printf '%b%b%4d'  "$fg"  "$bg"  "$n"
  done
  printf '%b\n' '\e[0m'
done

# 24 grayscale colors -> 232...255

for i in $(seq 0 23); do
  n=$(( 232 + i ))
  [ $i -lt 12 ] && fg="$white" || fg="$black"
  bg="\e[48;5;${n}m"
  printf '%b%b%4d  '  "$fg"  "$bg"  "$n"
done
printf '%b\n' '\e[0m'