Here's a version for fish, goes in ~/.config/fish/config.fish

  # MOTD
    function echo_color
      printf "\033[0;90m$argv[1]\033[0m\n"
    end
    echo_color "c-f  Move forward"
    echo_color "c-b  Move backward"
    echo_color "c-p  Move up"
    echo_color "c-n  Move down"
    echo_color "c-a  Jump to beginning of line"
    echo_color "c-e  Jump to end of line"
    echo_color "c-d  Delete forward"
    echo_color "c-h  Delete backward"
    echo_color "c-k  Delete forward to end of line"
    echo_color "c-u  Delete entire line"

And a slightly optimized bash version (YMMV):

  # MOTD
    function echo_color() {
      printf "\033[0;90m$1\033[0m\n"
    }
    echo_color "c-f  Move forward"
    echo_color "c-b  Move backward"
    echo_color "c-p  Move up"
    echo_color "c-n  Move down"
    echo_color "c-a  Jump to beginning of line"
    echo_color "c-e  Jump to end of line"
    echo_color "c-d  Delete forward"
    echo_color "c-h  Delete backward"
    echo_color "c-k  Delete forward to end of line"
    echo_color "c-u  Delete entire line"