Generalize a RHEL/CentOS VM for cloning

rhel_vm_clone_prep.sh

#!/bin/bash

# Would like this to work on RHEL/CentOS 6/7, but only tested on CentOS 7.

# unset HISTFILE; > ~/.bash_history; bash <(curl -sL https://goo.gl/ZbtT5z)

if [ -s ~/.bash_history ]; then
  read -p "Stop script to manually clear history? <y/n>: [N] " prompt
  if [[ $prompt =~ [yY](es)* ]]; then
    echo "Command: unset HISTFILE; > ~/.bash_history"
    exit
  fi
fi

# Stop logging
/sbin/service rsyslog stop
/sbin/service auditd stop

# Clean old kernels
which package-cleanup 1>&- 2>&- && HAVE_YUM_UTILS=true || yum install yum-utils -y 
/usr/bin/package-cleanup --oldkernels --count=1
if [ ! $HAVE_YUM_UTILS ] ; then yum remove yum-utils -y; fi

# Clean yum cache
/usr/bin/yum clean all

# Remove udev hardware rules (not present on CentOS 7)
/bin/rm -f /etc/udev/rules.d/70-persistent-net.rules

# Remove nic mac addr and uuid from ifcfg scripts
/bin/sed -i '/^\(HWADDR\|UUID\)=/d' /etc/sysconfig/network-scripts/ifcfg-eth0
/bin/rm -f /etc/sysconfig/network-scripts/ifcfg-ens*

# Remove host keys (important step security wise. similar to system GUID in Windows)
/bin/rm -f /etc/ssh/*key*

# Force the logs to rotate & cleanup old logs we don’t need 
/usr/sbin/logrotate -f /etc/logrotate.conf
/bin/rm -f /var/log/*-???????? /var/log/*.gz
/bin/rm -f /var/log/dmesg.old
/bin/rm -rf /var/log/anaconda
/bin/cat /dev/null > /var/log/audit/audit.log
/bin/cat /dev/null > /var/log/wtmp
/bin/cat /dev/null > /var/log/lastlog
/bin/cat /dev/null > /var/log/grubby

# Empty tmp
/bin/rm -rf /tmp/*
/bin/rm -rf /var/tmp/*

# Cleanup home directory
#/bin/rm -f ~root/anaconda-ks.cfg
/bin/rm -f ~/.ssh/id*
/bin/rm -f ~/.ssh/known_hosts
read -p "Remove authorized_keys? <y/n>: [N] " prompt
if [[ $prompt =~ [yY](es)* ]]; then
  /bin/rm -f ~/.ssh/authorized_keys
fi

# Clear bash history
unset HISTFILE
> ~/.bash_history

# Set random hostname
NEWHOST=$(cat /dev/urandom | tr -dc 'a-z' | head -c12)
which hostnamectl 1>&- 2>&- && hostnamectl set-hostname $NEWHOST || echo $NEWHOST > /etc/hostname

# Shutdown
read -p "Shutdown? <y/n>: [N] " prompt
if [[ $prompt =~ [yY](es)* ]]; then
  init 0
fi