Easy script to set hostname in Linux

sethostname.sh

#!/bin/bash
# @discription    Installation script for lamp
# @author         Mansour Yaacoubi
# @filename       sethostname.sh
# @todos          add better documentation, add support for other distributions
curhostname=$(hostname)
newhostname=$1

################# CHECK WHETHER SCRIPT IS RUNNING AS ROOT #################
# Run script as root to be able to install software like
# LAMP, composer and laravel
if [ "$EUID" -ne 0 ]
then echo "Please run as root"
  exit 1
else
  clear
  echo
  echo "Script is running with higher privileges as: $SUDO_USER -> $(whoami)"
  echo
fi

if [ "$newhostname" == "" ]
then
  echo "Missing argument: hostname"
  echo "Please provide an argument to set hostname"
  exit 1
fi

hostnamectl set-hostname $newhostname
hostname $newhostname
sed -i -e 's/'$curhostname'/'$newhostname'/g' /etc/hosts
echo $newhostname > /etc/hostname


oldremoved=$(hostnamectl | grep $curhostname)
oldremoved=$oldremoved$(hostname | grep $curhostname)
oldremoved=$oldremoved$(cat /etc/hosts | grep $curhostname)
oldremoved=$oldremoved$(cat /etc/hostname | grep $curhostname)

newadded=0
if [ "$(hostnamectl | grep $newhostname)" != "" ]; then newadded=$(expr $newadded + 1); fi;
if [ "$(hostname | grep $newhostname)" != "" ]; then newadded=$(expr $newadded + 1); fi;
if [ "$(cat /etc/hosts | grep $newhostname)" != "" ]; then newadded=$(expr $newadded + 1); fi;
if [ "$(cat /etc/hostname | grep $newhostname)" != "" ]; then newadded=$(expr $newadded + 1); fi;

if [ "$oldremoved" == "" ] && [ $newadded -eq 4 ]; then
  echo "Hostname set successfully."
  echo "Restarting in 3 seconds..."
  sleep 3
  service lightdm restart
else
  echo "[ERROR] Hostname not set."
  echo "Old hostname check output: "$oldremoved
  echo "Changed files: "$newadded
  exit 1
fi