#!/bin/bash
#backup.sh -- bash backup shell script
#
# by sp1r1t : tim <at> sp1r1t <dot> de
# do with this script whatever you want, but don't blame me (BSD license)
#
# history
#
# 2005-02-03 spirit : - changed .gz to .bz2
#                     - take lost+count directory into account when deleting files
#                     - adapted wrong comments / maxbackup numbers
#                     - fixed $PATH issue




# to run this script from cron under the root account :
#
#   as root, use "crontab -e" to edit your crontab. format is as follows :
#
#
#   minute(0-59)  hour(0-23)  day of month(1-31)  month(1-12 or Jan-Dec)  day of week(0-6 or Sun-Sat)  command 
#
#      0                    22               *                      *                  *               /root/backup.sh
#
# the last line expects this script to be located at /root/backup.sh and executes it at 10PM on every day.




########################################
# settings - adapt these to your needs #
########################################


# the directories this script should make backups of
backupdirs="/etc /root /home"


# path were the logfiles this script produces should be kept
logpath="/backup/logs"


# the path were the backups should be stored
backuptarget="/backup"


# maximal number of old backups to keep in the backup directory
# if more backups (not single .tar files) are in there, the oldest ones will be deleted
# example : if you backup 3 directories per day and set maxbyckups to  30,
# backups for  10 days (3 x 10 .tar.bz2-files)  will be kept
maxbackups=60

#################################
# prepare files and directories #
#################################


# make sure that PATH is set cause we need external programs from those dirs
export PATH=/bin:/usr/bin:$PATH


# get date in appropriate format to construct file names
today=`date +"%Y-%m-%d"`


# make sure the directories we need are present
if [ ! -d $logpath ]
then
echo "backup.sh WARNING : $logpath does not exist, creating it"
mkdir -p $logpath
chmod 0700 $logpath 
fi


# create logfile for today
touch $logpath/$today.log


# we are really lazy
logfile="$logpath/$today.log"


# check if logfile is there
if [ ! -e $logfile ]
then
echo "backup.sh WARNING : could not create logfile at $logfile"
fi


###############################
# deal with old backups files #
###############################

cd $backuptarget

# count old backup files
fcount=`echo *.tar.bz2 | wc -w | awk '{print $1}'`
echo "$fcount old backup file(s) present"

# rm the oldest files if $maxbackups is exceeded
# example : if $maxbackups is 10 and there are 13 files, delete the oldest 3 of them
if [ $fcount -gt $maxbackups ]
then

  # get number of files that should be erased
  deathcount=$(expr $fcount - $maxbackups)
  echo "deathcount : $deathcount"

  if [ $deathcount -lt 0 ]
  then
  $deathcount=0
  fi
  echo "corrected deathcount : $deathcount"

  deadfiles=`ls -Ac | tail -n $deathcount`


  for dfile in $deadfiles
  do
    if [ ! $dfile eq "lost+found" ]
    then
    rm $dfile
    echo "$dfile was deleted"
    fi
  done

fi

###########################
# deal with old log files #
###########################

# old log files are simply left alone
# rename existing backup files of today if they are already present
# ( this should only be the case if this script is run more than once daily )

cd $logpath

# make sure we start a fresh logfile
if [ -f $today.log ]
then

  # get current time in appropriate format to construct file names
 secs=`date +"%s"`

 # blare out
 echo "backup file with current date exists, renaming it to $secs" #| wall

 # rename old file to a unique name
 mv $today.log $secs.log

fi

######################################
# prepare and perform backup process #
######################################


# what's a logfile without some info?
cur_time=`date`
echo "this file was created by the backup script $0" >>$logfile
echo "   " >>$logfile
echo "starting backup at $cur_time" >>$logfile




# something might be wrong if this doesn't exist
if [ ! -d $backuptarget ]
then
echo "backup.sh WARNING : $backuptarget does not exist, creating it at $backuptarget" >>$logfile
mkdir -p $backuptarget
chmod 0700 $backuptarget
fi


# what about finally doing what we came for?
for path in $backupdirs
do
    echo "starting backup of $path..." >>$logfile
    $path=`echo $path | sed 's/\//-/g'`
    tar cjvf $backuptarget/$path-$today.tar.bz2 $path >>$logfile
    sleep 1
    echo "backup of $path finished" >>$logfile
done


# let's get a little verbose again
echo "...backup complete, status: $?" >>$logfile
echo "verifying backups..." >>$logfile


# fullfilling our promise : check the files you just produced, tar!
for path in $backupdirs
do
  echo "verifying $path...." >>$logfile
  tar tjvf $backuptarget/$path-$today.tar.bz2 >>$logfile && echo "$path verified, looks good" >>$logfile
  if [ $? -eq 0 ]
        then
        sleep 1
        else echo "WARNING : errors occured in $path" >>$logfile
  fi
done

#end of script