rbash-host() {
  local host="${1:-}"
  local domain="${2:-}"
  local color="${3:-}"

  if [ -z "$host" ] || [ -z "$domain" ]; then
    echo "Usage: rbash-host HOST DOMAIN [COLOR]" >&2
    echo "Example: rbash-host penguin @macstudio 6" >&2
    return 1
  fi

  mkdir -p "$RBASH_HOME"

  {
    printf 'RHOSTNAME=%q\n' "$host"
    printf 'RDOMAIN=%q\n' "$domain"
    if [ -n "$color" ]; then
      printf 'RCOLOR=%q\n' "$color"
    fi
  } > "$RBASH_ENV"

  echo "Wrote $RBASH_ENV"

  # shellcheck source=/dev/null
  source "$RBASH_ENV"

  __rbash_setup_prompt
}