#!/bin/bash

# show-all-colors.sh
# Displays all 256 possible background colors, using ANSI escape sequences.
# Author: Chetankumar Phulpagare
# Used in ABS Guide with permission.

T1=8
T2=6
T3=36
offset=0

for num1 in {0..7}
do {
   for num2 in {0,1}
       do {
          shownum=`echo "$offset + $T1 * ${num2} + $num1" | bc`
          echo -en "\E[0;48;5;${shownum}m color ${shownum} \E[0m"
          }
       done
   echo
   }
done

offset=16
for num1 in {0..5}
do {
   for num2 in {0..5}
       do {
          for num3 in {0..5}
              do {
                 shownum=`echo "$offset + $T2 * ${num3} \
                 + $num2 + $T3 * ${num1}" | bc`
                 echo -en "\E[0;48;5;${shownum}m color ${shownum} \E[0m"
                 }
               done
          echo
          }
       done
}
done

offset=232
for num1 in {0..23}
do {
   shownum=`expr $offset + $num1`
   echo -en "\E[0;48;5;${shownum}m ${shownum}\E[0m"
}
done

echo