linux备份文件脚本

#!/bin/sh
#Author: Opal
TODAY=`date +%Y%m%d`
YESTERDAY=`date -d"-1 day" +%Y%m%d`
mkdir -p /var/backups/etc.${TODAY}/
cp -r  /etc/*  /var/backups/etc.${TODAY}/
DIFF=`diff -r  /var/backups/etc.${TODAY}/ /var/backups/etc.${YESTERDAY}/`
if [$DIFF = ""];then
        rm -rf /var/backups/etc.${YESTERDAY}
else
        echo "Some file have changed!"
fi