#!/bin/bash
# This script makes a snapshot of several directories using rsync.

# Version 0.5, Rob Bos, September 8, 2002
# This script is released under the terms of the GNU General Public License, version 2.0.

# run "hourly" from a crontab; run daily, weekly, and monthly from /etc/cron.{daily,weekly,monthly}/.

[ -z "$1" ] && echo syntax: $0 snapshottype && exit 1

type=$1 # hourly, daily, monthly snapshot?
logfile=/var/log/snapshot.log
backuproot=/home/.backup
backup=`cat /etc/snapshot/include.text`
excludefile=/etc/snapshot/exclude.text

# if you run every two hours, make it 12, every hour, 24, etc.  try to span the entire day.
# The below setting runs 8 times a day (every three hours), keeps 7 days, 4 weeks, and 12 months
# of backup.
hourlymax=8
dailymax=7
weeklymax=4
monthlymax=12

# This simplifies things down below so I can use $max to delete
# the overrotated snapshot, as well as $hourlymax/$dailymax to do
# rotation checks.
[ $type == "hourly" ] && max=hourlymax
[ $type == "daily" ] && max=dailymax
[ $type == "weekly" ] && max=weeklymax
[ $type == "monthly" ] && max=monthlymax
	
# Rotate the current list of backups, if we can.
if [ -d $backuproot/$type.1 ]; then
	oldest=`ls -dt $backuproot/$type.* | tail -n 1 | sed 's/^.*\.//'`
	for i in `seq $oldest 1`; do
		mv $backuproot/$type.$i $backuproot/$type.$(( i + 1 ))
	done
fi

if [ "$type" == "hourly" ]; then
	# recreate directory structure with hard links.
	cp -al $backuproot/$type.2 $backuproot/$type.1
	rsync -va --delete --delete-excluded --exclude-from=$excludefile $backup $backuproot/$type.1/
elif [ "$type" == "daily" ]; then
	[ -d $backuproot/hourly.$hourlymax ] && mv $backuproot/hourly.$hourlymax $backuproot/daily.1
elif [  "$type" == "weekly" ]; then
	[ -d $backuproot/daily.$dailymax ] && mv $backuproot/daily.$hourlymax $backuproot/weekly.1
elif [  "$type" == "monthly" ]; then
	[ -d $backuproot/weekly.$weeklymax ] && mv $backuproot/weekly.$weeklymax $backuproot/monthly.1
elif [ "$type" == "symlinks" ]; then
	# assumes that /home is the only thing being backed up.  temporary thing.
	cd $backuproot;
	for i in /home/*;do 
		for f in *;do 
			ln -s $backuproot/$f/$i $i/.snapshot/$f
		done;
	done
fi

# if we've rotated the last backup off the stack, remove it.
[ -d $backuproot/$type.$((max+1)) ] && rm -rf $backuproot/$type.$((max+1))

# finally, let's make the new snapshot reflect the current date.
[ -d $backuproot/$type.1 ] && touch $backuproot/$type.1