Auto generate Hostname on Rhel 7 and auto-add into /etc/hosts

gistfile1.txt

#!/bin/bash
#### This script will create hostname for rhel 7 and add dns entries into /etc/hosts.
#### There is also a way to generate a random hostname, but the code is commented out.
#### Future version, will try to make it work for when user doesn't have any entry.

dom='.china.com'
old=$(hostname -f)

#This is if you want random letters.
#new2=$(tr -dc 'a-z0-9' < /dev/urandom | head -c12)

#### This prompts user for hostname and enters it in
read -p "Type in your hostname and then press enter : " yourhostname
new=$yourhostname$dom
hostnamectl set-hostname "$new"

### Lets get a read out of current ip.
oldip=$(sed '3!d' /etc/hosts | awk '{print $1}')
newip=$(ip -o -4 addr show dev eth0 | sed 's/.* inet \([^/]*\).*/\1/')

sed -i "s/$old/$new/g" /etc/hosts
sed -i "s/$oldip/$newip/g" /etc/hosts