For minimizing disk size of Centos 7 virtualbox machines for use with vagrant

shrink

#!/bin/bash

# Source: http://vstone.eu/reducing-vagrant-box-size/
# Modified by: Jason Yang [jason.yang at mercatustechnologies.com]

function pause() {
    read -p "$*"
}

cat - << EOWARNING
WARNING: This script will fill up your left over disk space.

DO NOT RUN THIS WHEN YOUR VIRTUAL HD IS RAW!!!!!!

You should NOT do this on a running system.
This is purely for making vagrant boxes damn small.

EOWARNING

pause "Press [Enter] key to continue... or [Ctrl-C] to abort."

echo 'Uninstall unnecessary packages'
yum erase -y dkms kernel-devel* kernel-headers
yum groupremove -y "Development Tools"

echo 'Remove unnecessary locales'
cd /usr/share/locale
find . -maxdepth 1 ! -name 'en_US' -type d -exec rm -Rf {} \;

echo 'Cleaning up yum cache'
yum clean all

echo 'Cleanup bash history'

# Unset the HISTFILE environment variable so that the history
# for the current session isn't saved when you exit
unset HISTFILE

# Remove all bash histories
find / -type f -name .bash_history -exec cp /dev/null {} \; -exec echo "Clearing history: {}" \;

echo 'Cleanup log files'
find /var/log -type f -exec cp /dev/null {} \; -exec echo "Truncating log file: {}" \;

echo 'Whiteout root'
count=`df --sync -kP / | tail -n1 | awk -F ' ' '{print $4}'`;
let count--
dd if=/dev/zero of=/tmp/whitespace bs=1024 count=$count;
rm /tmp/whitespace;

echo 'Whiteout /boot'
count=`df --sync -kP /boot | tail -n1 | awk -F ' ' '{print $4}'`;
let count--
dd if=/dev/zero of=/boot/whitespace bs=1024 count=$count;
rm /boot/whitespace;

swappart=`cat /proc/swaps | tail -n1 | awk -F ' ' '{print $1}'`;
echo "Truncating swap file: $swappart"
swapoff $swappart;
dd if=/dev/zero of=$swappart;
mkswap $swappart;
swapon $swappart;