8-bit (256) terminal colours

[michael-franzese]

Am getting confused about 8-bit (256) colours.

For 4-bit colours, I can understand the codes

\e[0;${bg};${fg}m  bg=(40..47), fg=(30..37)

But for 8-bit colours I have tried

\e[${fg};5;${bg}m  bg=(0..255), fg=(0..255)

Below is my attempt

     bi="38"
     for fi in {0..255} ; do
       # Display the color
       printf "\e[${fi};5;%sm  %3s  \e[0m" $bi $fi
       # Display 8 colors per lines
       if [ $((($fi + 1) % 8)) == 0 ] ; then
         echo # New line
       fi
     done