In startup.sh, here are a few things to think about.

Instead of setting RED/GREEN/BLUE, you could do this:

  N=$(printf \\033)
  N="$N[" x=30

  for a in Bl R G Y B M C W  # Black Red Green Yellow Blue Magenta Cyan White
  do eval $a='$N'"'"$((     x))"m'" \
         b$a='$N'"'"$((60 + x))"m'" \
      ${a}bg='$N'"'"$((10 + x))"m'" \
     b${a}bg='$N'"'"$((70 + x))"m'" # bX=bright Xbg=background bXbg=brgt bgnd
     x=$(( x + 1 ))
  done                       # https://en.wikipedia.org/wiki/ANSI_escape_code

Unless you have "set -e" this:

  if [ ! "$HOSTNAME" ]; then
    HOSTNAME="$(hostname -s)"
  fi

Is more succinctly expressed as this:

  [ -z "$HOSTNAME" ] && HOSTNAME="$(hostname -s)"