mysqldump with gzip(monthly)

backup.sh

#!/bin/bash

_dir='/path/to/target/'
_target=`date +"%Y%m"`

if test ! -d $_dir$_target
then
  mkdir $_dir$_target

  _last=`date -d '1 month ago' +"%Y%m"`

  if test -d $_dir$_last
  then
    cd $_dir
    tar cvzf ${_last}.tar.gz $_last
    rm -rf $_dir$_last
  fi
fi

_file=`date +"%Y-%m-%d"`
cd $_dir$_target
mysqldump -uxxx -pxxx database > ${_file}.sql