test your terminal's colors.

color-test.sh

#!/bin/bash
#
#   This file echoes a bunch of color codes to the 
#   terminal to demonstrate what's available.  Each 
#   line is the color code of one forground color,
#   out of 17 (default + 16 escapes), followed by a 
#   test use of that color on all nine background 
#   colors (default + 8 escapes).
#

T='gYw'   # The test text

echo -e "\n                 40m     41m     42m     43m     44m     45m     46m     47m";

for FGs in '    m' '   1m' '  30m' '1;30m' '  31m' '1;31m' '  32m' \
           '1;32m' '  33m' '1;33m' '  34m' '1;34m' '  35m' '1;35m' \
           '  36m' '1;36m' '  37m' '1;37m';
    do
        FG=${FGs// /}
        echo -en " $FGs \033[$FG  $T  "
        for BG in 40m 41m 42m 43m 44m 45m 46m 47m; do
            echo -en " \033[$FG\033[$BG  $T  \033[0m";
        done
        echo;
    done
echo

echo "To use, take the code at the side, combine with the code on the top."
echo "For example, the bold white on blue is \\033[44m\\033[1m.  Like this:"
echo -e "\033[1m\033[44mwhite on blue!\033[0m"
# exit 0
# The default xterm 256 colour palette
for red in 0 1 2 3 4 5; do
  for green in 0 1 2 3 4 5; do
    for blue in 0 1 2 3 4 5; do
        c=$((16 + ($red * 36) + ($green * 6) + $blue))
        r=$((($red ? ($red * 40 + 55) : 0)))
        g=$((($green ? ($green * 40 + 55) : 0)))  
        b=$((($blue ? ($blue * 40 + 55) : 0)))
				# if [ $r -eq $g ] && [ $r -eq $b ]; then
					echo -ne "\033[38;5;${c}m 38;5;${c}[${r},${g},${b}] \033[0m"
				# fi
        # printf ".ef%d { color: #%2.2x%2.2x%2.2x; } " $c $r $g $b
        # printf ".eb%d { background-color: #%2.2x%2.2x%2.2x; }\n" $c $r $g $b
    done
		echo ""
  done
done
exit 0
for gray in 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23; do
  c=$(($gray+232))
  l=$(($gray*10 + 8))
  printf ".ef%d { color: #%2.2x%2.2x%2.2x; } " $c $l $l $l
  printf ".eb%d { background-color: #%2.2x%2.2x%2.2x; }\n" $c $l $l $l
done