#!/bin/sh
# full and incremental backup script

#Change the 5 variables below to fit your computer/backup

COMPUTER=orion                                  # name of this computer
DIRECTORIES=/share                              # directoris to backup
BACKUPDIR=/backup                               # where to store the backups
TIMEDIR=/backup/last-full                       # where to store time of full backup
TAR=/bin/tar                                    # name and locaction of tar

#You should not have to change anything below here

DOW=`date +%a`                          # Day of the week e.g. Mon
DOM=`date +%d`                          # Date of the Month e.g. 27
DM=`date +%d%b`                         # Date and Month e.g. 27Sep

# On the 1st of the month a permanet full backup is made
# Every Sunday a full backup is made - overwriting last Sundays backup
# The rest of the time an incremental backup is made. Each incremental
# backup overwrites last weeks incremental backup of the same name.
#


# Monthly full backup
if [ $DOM = "01" ]; then
        NEWER=""
        $TAR -cf $BACKUPDIR/$COMPUTER-$DM.tar $DIRECTORIES
fi

# Weekly full backup
if [ $DOW = "Sun" ]; then
        NOW=`date +%d-%b`

        # Udate full backup date
        echo $NOW > $TIMEDIR/$COMPUTER-full-date

        $TAR -cf $BACKUPDIR/$COMPUTER-$DOW.tar $DIRECTORIES

# Make incremental backup - overwrite last weeks
else

        # Get date of last full backup
        NEWER="--newer `cat $TIMEDIR/$COMPUTER-full-date`"
        $TAR $NEWER -ucf $BACKUPDIR/$COMPUTER-$DOW.tar $DIRECTORIES
fi