tabela de cores script

digite no terminal a linha abaixo 

for x in {0..8}; do for i in {30..37}; do for a in {40..47}; do echo -ne "\e[$x;$i;$a""m\\\e[$x;$i;$a""m\e[0;37;40m "; done; echo; done; done; echo ""

ou

para ver as 256 cores

#!/usr/bin/bash   
for i in {0..255} ; do
  printf "\x1b[38;5;${i}m██-${i} "
done