#!/bin/bash

IP="$(ip a show scope global \
  | grep inet \
  | head -1 \
  | sed -r 's#.*inet ([0-9]+.[0-9]+.[0-9]+.[0-9]+.)/.*#\1#')"
HOSTNAME="$(dig +noall +answer +short -x "$IP" \
  | head -1 \
  | sed 's/\.$//')"

# Set hostname and renew DHCP lease
sudo hostnamectl set-hostname "${HOSTNAME}"
sudo dhclient -r
sleep 1
sudo dhclient