Linux shell script to check and compare file consistency

#!/bin/bash
check_dir=/var/html/www
zhiwendb="/opt/zhiwen.db" #原始指纹库路径
filedb="/opt/wenjian.db" #原始文件库路径
errlog="/opt/err.log" #监测后的内容日志

[ -e $check_dir ] || exit 1 #目录不存在就退出脚本
[ -e $zhiwendb ] || exit 1
[ -e $filedb ] || exit 1

echo "`md5sum -c --quiet /opt/zhiwen.db`" > $errlog #  将错误日志存放在指定位置
md5sum -c --quiet /opt/zhiwen.db &> /dev/null

find $check_dir -type f > /opt/wenjian.db_curr
echo "`diff /opt/wenjian.db*`" &>>$errlog
diff /opt/wenjian.db* &>> $errlog

if [ $? -ne 0 -o `diff /opt/wenjian.db* |wc -l` -ne 0 ];then
    touch /tmp/`date +%s`.err #  在指定位置创建错误报警提示 -o就是&&
else
    echo "sites dir is ok"
fi