Here is the script that I am using for backing up my SQL databases on the websites that I have.

click on the read more, to see the script.

I have also added tha last line, witch will make sure that you only keep the last 7 days's of databases.

#!/bin/bash
# Shell script to backup MySql database
# To backup Nysql databases file to /backup dir and later pick up by your
# script. You can skip few databases from backup too.
# For more info please see (Installation info):
# http://www.cyberciti.biz/nixcraft/vivek/blogger/2005/01/mysql-backup-script.ht
ml
# Last updated: Aug - 2005
# --------------------------------------------------------------------
# This is a free shell script under GNU GPL version 2.0 or above
# Copyright (C) 2004, 2005 nixCraft project
# Feedback/comment/suggestions : http://cyberciti.biz/fb/
# -------------------------------------------------------------------------
# This script is part of nixCraft shell script collection (NSSC)
# Visit http://bash.cyberciti.biz/ for more information.
# -------------------------------------------------------------------------

# -------------------------------------------------------------------------
# Own private Scribbeles (Updated 2006-02-01)
# Make one user, that only have "read" right for all your databases
#User Right: Read only 'select'
# -------------------------------------------------------------------------
MyUSER="SQL_user"     # USERNAME
MyPASS="SQL_user_passwd"       # PASSWORD
MyHOST="sqlServer"          # Hostname

# Linux bin paths, change this if it can't be autodetected via which command
MYSQL="$(which mysql)"
MYSQLDUMP="$(which mysqldump)"
CHOWN="$(which chown)"
CHMOD="$(which chmod)"
GZIP="$(which gzip)"

# Backup Dest directory, change this if you have someother location
DEST="fill out where you want your backupo"

# Main directory where backup will be stored
MBD="$DEST/mysql"

# Get hostname
HOST="$(hostname)"

# Get data in dd-mm-yyyy format
NOW="$(date +"%d-%m-%Y")"

# File to store current backup file
FILE="$FileName"
# Store list of databases
DBS="$DBList.txt"

# DO NOT BACKUP these databases
IGGY="test"

[ ! -d $MBD ] && mkdir -p $MBD || :

# Only root can access it!
$CHOWN 0.0 -R $DEST
$CHMOD 0600 $DEST

# Get all database list first
DBS="$($MYSQL -u $MyUSER -h $MyHOST -p$MyPASS -Bse 'show databases')"

for db in $DBS
do
skipdb=-1
if [ "$IGGY" != "" ];
then
for i in $IGGY
do
[ "$db" == "$i" ] && skipdb=1 || :
done
fi

if [ "$skipdb" == "-1" ] ; then
FILE="$MBD/$db.$HOST.$NOW.gz"
# do all inone job in pipe,
# connect to mysql using mysqldump for select mysql database
# and pipe it out to gz file in backup dir :)
$MYSQLDUMP -u $MyUSER -h $MyHOST -p$MyPASS $db | $GZIP -9 > $FILE
fi
done
#
#
# Call Cleanup, remove 7days old files
find "$DEST/mysql" -type f -mtime +7 |grep gz |xargs rm -fv