#!/bin/sh
# Author: Brice Burgess - [email protected]
# multi_backup.sh -- backup to a local drive using rsync.
#         Uses hard-link rotation to keep multiple backups.

# Directories to backup. Seperate with a space. Exclude trailing slash!
SOURCES="/home/gig"

# Directory to backup to. This is where your backup(s) will be stored. No spaces in names!
# :: NOTICE :: -> Make sure this directory is empty or contains ONLY backups created by
#	                        this script and NOTHING else. Exclude trailing slash!
TARGET="/tmp/shares/Backups/LinuxLap"

# Set the number of backups to keep (greater than 1). Ensure you have adaquate space.
ROTATIONS=2

# Your EXCLUDE_FILE tells rsync what NOT to backup. Leave it unchanged if you want
# to backup all files in your SOURCES. If performing a FULL SYSTEM BACKUP, ie.
# Your SOURCES is set to "/", you will need to make use of EXCLUDE_FILE.
# The file should contain directories and filenames, one per line.
# A good example would be:
# /proc
# /tmp
# *.SOME_KIND_OF_FILE
EXCLUDE_FILE="/home/gig/gitclones/*
/home/gig/github/*
/home/gig/.emacs
/home/gig/.emacs.d
/home/gig/.awesome.ctl.0=
/home/gig/.rxvt-unicode-gigNote=
/home/gig/.pine-debug*
/home/gig/.serverauth.*
/home/gig/.zsh/history
/home/gig/.irb_history
/home/gig/.myXLog"

# Comment out the following line to disable verbose output
VERBOSE="-v"

#######################################
########DO_NOT_EDIT_BELOW_THIS_POINT#########
#######################################

# Set name (date) of backup.
BACKUP_DATE="`date +%F_%H-%M`"

if [ ! -x $TARGET ]; then
  echo "Backup target does not exist or you don't have permission!"
  echo "Exiting..."
  exit 2
fi

if [ ! $ROTATIONS -gt 1 ]; then
  echo "You must set ROTATIONS to a number greater than 1!"
  echo "Exiting..."
  exit 2
fi

#### BEGIN ROTATION SECTION ####

BACKUP_NUMBER=1
# incrementor used to determine current number of backups

# list all backups in reverse (newest first) order, set name of oldest backup to $backup
# if the retention number has been reached.
for backup in `ls -dXr $TARGET/*/`; do
	if [ $BACKUP_NUMBER -eq 1 ]; then
		NEWEST_BACKUP="$backup"
	fi

	if [ $BACKUP_NUMBER -eq $ROTATIONS ]; then
		OLDEST_BACKUP="$backup"
		break
	fi

	let "BACKUP_NUMBER=$BACKUP_NUMBER+1"
done

# Check if $OLDEST_BACKUP has been found. If so, rotate. If not, create new directory for this backup.
if [ $OLDEST_BACKUP ]; then
  # Set oldest backup to current one
  mv $OLDEST_BACKUP $TARGET/$BACKUP_DATE
else
	mkdir $TARGET/$BACKUP_DATE
fi

# Update current backup using hard links from the most recent backup
if [ $NEWEST_BACKUP ]; then
  cp -al $NEWEST_BACKUP. $TARGET/$BACKUP_DATE
fi
#### END ROTATION SECTION ####


# Check to see if rotation section created backup destination directory
if [ ! -d $TARGET/$BACKUP_DATE ]; then
  echo "Backup destination not available. Make sure you have write permission in TARGET!"
  echo "Exiting..."
  exit 2
fi

echo "Verifying Sources..."
for source in $SOURCES; do
	echo "Checking $source..."
	if [ ! -x $source ]; then
     echo "Error with $source!"
     echo "Directory either does not exist, or you do not have proper permissions."
     exit 2
   fi
done

if [ -f $EXCLUDE_FILE ]; then
	EXCLUDE="--exclude-from=$EXCLUDE_FILE"
fi

echo "Sources verified. Running rsync..."
for source in $SOURCES; do

  # Create directories in $TARGET to mimick source directory hiearchy
  if [ ! -d $TARGET/$BACKUP_DATE/$source ]; then
    mkdir -p $TARGET/$BACKUP_DATE/$source
  fi

  rsync $VERBOSE --exclude=$TARGET/ $EXCLUDE -a --delete $source/ $TARGET/$BACKUP_DATE/$source/

done

exit 0