#!/bin/bash

# This script makes a snapshot of several directories using rsync.
# It's based on Rob Bos's snapshot script found at mikerubel.org.

# Version 0.1, Geordy Kitchen, November 26, 2002
# This script is released under the terms of the GNU General Public License,
# version 2.0.

# Your crontab will typically look something like this:
# 0 */4 * * * /bin/this_script hourly
# 59 3 * * * /bin/this_script daily
# 58 3 * * 0 /bin/this_script weekly
# 57 3 1 * * /bin/this_script monthly

# Configuration

  # Destination directory.
dst=/backup

srcroot="user1@hostname"

  # Use a trailing slash for directories, just the filename for files.
src="/var/mail/user1 /home/user1/"

  # Number of times to run per day.
hourly=6

# Constants
daily=7
weekly=4
monthly=12

case $1 in 
    hourly)
        [ -d $dst/$1.1 ] && cp -al $dst/$1.1 $dst/$1.0
        for i in $src; do
	    dirdst=`echo $i | sed 's|^/||; s|[^/]*$||'`
	    [ -d $dst/$1.0/$dirdst ] || mkdir -p $dst/$1.0/$dirdst
	    rsync -a --delete $srcroot:$i $dst/$1.0/$dirdst
	done
	;;
    daily)
        [ -d $dst/hourly.$hourly ] && mv $dst/hourly.$hourly $dst/daily.0
	;;
    weekly)
	[ -d $dst/daily.$daily ] && mv $dst/daily.$daily $dst/weekly.0
	;;
    monthly)
	[ -d $dst/weekly.$weekly ] && mv $dst/weekly.$weekly $dst/monthly.0
	;;
    *)
	echo "syntax: $0 <type>"
        exit 1
	;;
esac

# Rotate the current list of backups, if we can.
if [ -d $dst/$1.0 ]; then
	oldest=`ls -d $dst/$1.* | tail -n 1 | sed 's/^.*\.//'`
	for i in `seq $oldest 0`; do
	    mv $dst/$1.$i $dst/$1.$((i+1))
	done
fi

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

# finally, let's make the new snapshot reflect the current date.
[ -d $dst/$1.1 ] && touch $dst/$1.1