Modify hostname

edit-hostname.sh

#!/usr/bin/env bash

newHostname=$1

if [[ "$newHostname" == "" ]];
then
  echo "Please set 1 parameter"
  echo "$0 hostname"
  exit 1
fi

oldHostname=$(hostname)
hostnamectl set-hostname $newHostname

while read ip address;
do
    hosts=''
    for host in $address;
    do
      if [[ $host == "$oldHostname" ]];
      then
        host="$newHostname"
      fi
      hosts="$hosts $host"
    done
    sed -i "s/^$ip.*$/$ip$hosts/g" /etc/hosts
done < <(cat /etc/hosts | grep -vP "(^#|^$)")