#!/bin/bash
# simple backup script for everyday cron execution
# after execution `crontab -e` add new line to crontab schedule:
# @daily sh /home/user/backup.sh

# files and dirs for backup:
backups[0]=/home/user/some.file
backups[1]=/home/user/somedir
# dir for archives:
SAVEDIR=/home/user/archive/
# number of days for backup
DAYS=5
WEEKS=10

# create archive with file name 'arc.tar.gz'
tar -cvzf ${SAVEDIR}arc.tar.gz ${backups[*]}

# save last WEEKS
if [ -e ${SAVEDIR}arc-w1.tar.gz ]
then
    oneweek=${SAVEDIR}arc-w1.tar.gz
    oneweekripen=`find ${SAVEDIR}arc-w1.tar.gz -type f -mtime +10`
    echo $oneweek
    echo $oneweekripen
    if [ "$oneweek" = "$oneweekripen" ]
    then
        for ((a=WEEKS; a >= 2 ; a--))
        do
            let b=a-1
            mv ${SAVEDIR}arc-w${b}.tar.gz ${SAVEDIR}arc-w${a}.tar.gz
        done
        mv ${SAVEDIR}arc-d5.tar.gz ${SAVEDIR}arc-w1.tar.gz
    fi
else
    mv ${SAVEDIR}arc-d5.tar.gz ${SAVEDIR}arc-w1.tar.gz
fi

# save last DAYS
for ((a=DAYS; a >= 2 ; a--))
do
    let b=a-1
    mv ${SAVEDIR}arc-d${b}.tar.gz ${SAVEDIR}arc-d${a}.tar.gz
done
mv ${SAVEDIR}arc.tar.gz ${SAVEDIR}arc-d1.tar.gz

exit 0