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shell编程19例

www.someabcd.com  网友分享于:Jun 8, 2018 5:53:24 PM

标签:shell   mysql   

 


<!--StartFragment -->

<div>


本文所有题目来自于老男孩51cto博客,地址如下:


http://oldboy.blog.51cto.com/2561410/1632876


转载请注明最原始出处。


本文中所有题目答案都是按我自己的思路整理的,并不代表最完美答案,适合新手学习参考。


</div>

<div></div>

<div>由于代码是从word中复制过来的,文章发布后发现所有的代码格式都乱了(一律左对齐了),╮(╯▽╰)╭,之后又用了很长时间手动更改代码的格式,因为是手动,难免有疏忽,而且改的也不是很规范,格式上错乱的地方望见谅。</div>

<div> 毕竟shell编程第一步就是格式嘛!</div>

&nbsp;


目录:


<a href="#_Toc420786634">1       监控mysql主从同步</a>


<a href="#_Toc420786635">2       批量创建文件</a>


<a href="#_Toc420786636">3       批量改名</a>


<a href="#_Toc420786637">4       批量创建账户</a>


<a href="#_Toc420786638">5       判断当前局域网存在的主机</a>


<a href="#_Toc420786639">6       写一个脚本解决DOS攻击生产案例</a>


<a href="#_Toc420786640">7       开发mysql多实例启动脚本</a>


<a href="#_Toc420786641">8       对MySQL数据库进行分库备份</a>


<a href="#_Toc420786642">9       对MySQL数据库进行分库加分表备份</a>


<a href="#_Toc420786643">10         字符串打印</a>


<a href="#_Toc420786644">11          计算比较</a>


<a href="#_Toc420786645">12         打印菜单(堡垒机</a>


<a href="#_Toc420786646">13         检测web服务及mysql服务</a>


<a href="#_Toc420786647">14         监控memcached</a>


<a href="#_Toc420786648">15         监控web站点目录是否被篡改</a>


<a href="#_Toc420786649">16         rsync服务启动脚本</a>


<a href="#_Toc420786650">17         抓阄题</a>


<a href="#_Toc420786651">18         暴力破解密码</a>


<a href="#_Toc420786652">19         批量检查多个网站地址是否正常</a>


&nbsp;


&nbsp;

<h1><a name="_Toc420786634"></a>1         监控mysql主从同步</h1>

(生产实战案例):监控MySQL主从同步是否异常,如果异常,则发送短信或者邮件给管理员。提示:如果没主从同步环境,可以用下面文本放到文件里读取来模拟:

阶段1:开发一个守护进程脚本每30秒实现检测一次。

阶段2:如果同步出现如下错误号(1158,1159,1008,1007,1062),则跳过错误。

阶段3:请使用数组技术实现上述脚本(获取主从判断及错误号部分)

<pre class="brush:shell">#!/bin/bash


#lixinyu linux


#2015-5-15


#监控mysql主从同步


 


USER=root


PASSWORD=123456


PORT=3307


error=(1158 1159 1008 1007 1062)


MYSQLCMD="mysql -u$USER -p$PASSWORD -S /data/$PORT/mysql.sock"


 


is_run(){


[ `lsof -i:$PORT|wc -l` -lt 2 ]&amp;&amp;{


    echo "mysql server is stoping"


    exit 1


  }


}


 


status_array(){


status=($($MYSQLCMD -e "show slave status\G"|egrep "_Running|Last_Errno|Behind_Master"|awk ‘{print $NF}‘))


}


 


status_error(){


flag=0


for((i=0;i&lt;${#error[*]};i++))


do


  if [ "$1" == "${error[$i]}" ]


    then


      $MYSQLCMD -e "stop slave;set global sql_slave_skip_counter=1;start slave;"


    else


    let flag=flag+1


  fi


done


[ $flag -ne 0 ]&amp;&amp;echo "MySQL slave is failed, errorno is $1"


}


 


judge_slave(){


status_array


if [ "${status[0]}" == "Yes" -a "${status[1]}" == "Yes" -a "${status[3]}" = "0" ]


  then


    echo "MySQL slave is ok"


  else


    status_error ${status[2]}


fi


}


 


main(){


while true


do


  is_run


  judge_slave


  sleep 5


done


}


main


</pre>

&nbsp;

<h1><a name="_Toc420786635"></a>2         批量创建文件</h1>

使用for循环在/oldboy目录下通过随机小写10个字母加固定字符串oldboy批量创建10个html文件,名称例如为:


jdxexendbe_oldboy.html  ugaywanjlm_oldboy.html  xzzruhdzda_oldboy.html


qcawgsrtkp_oldboy.html  vfrphtqjpc_oldboy.html


解答脚本

<pre class="brush:shell">#!/bin/bash


 


if [ ! -d /oldboy ]


  then


    mkdir /oldboy -p


fi


 


for ((i=1;i&lt;=10;i++))


do


  touch /oldboy/`echo $RANDOM|md5sum|cut -c 1-10`_oldboy.html


done


</pre>

&nbsp;

<h1><a name="_Toc420786636"></a>3         批量改名</h1>

将以上文件名中的oldboy全部改成oldgirl(用for循环实现),并且html改成大写。请用两种以上方法实现


方法一

<pre class="brush:shell">#!/bin/bash


 


cd /oldboy


name=($(ls /oldboy))


for ((i=0;i&lt;${#name[*]};i++))


do


  /bin/mv ${name[i]} `ls ${name[i]}|sed -rn ‘s#(^.*)_oldboy.html#\1_oldgirl.HTML#gp‘`


done


</pre>

改回来(也可以作为一种方法)


rename "oldgirl.HTML" "oldboy.html" *.HTML


方法二

<pre class="brush:shell">#!/bin/bash


cd /oldboy


for f in `ls /oldboy`


do


  /bin/mv $f `echo $f|sed -rn ‘s#(^.*)oldboy.html#\1oldgirl.HTML#gp‘ `


done


</pre>

<h1><a name="_Toc420786637"></a>4         批量创建账户</h1>

批量创建10个系统帐号oldboy01-oldboy10并设置密码(密码为随机8位字符串)。

<pre class="brush:shell">#!/bin/bash



random(){


password=`echo $RANDOM|md5sum|cut -c 1-8`


}


 


for user in `seq  -w 10`


do


  useradd oldboy$user


  random


  echo $password|passwd --stdin oldboy$user


  echo oldboy$user $password &gt;&gt;/opt/user.txt


done


</pre>

<h1><a name="_Toc420786638"></a>5         判断当前局域网存在的主机</h1>

写一个脚本,实现判断10.0.0.0/24网络里,当前在线用户的IP有哪些(方法有很多)

<pre class="brush:shell">#!/bin/bash


. /etc/init.d/functions


 


for ((i=1;i&lt;=254;i++))


do


  ping -c1 10.0.0.$i &gt;/dev/null 2&gt;&amp;1


  if [ $? -eq 0 ]


    then


      action "10.0.0.$i is ok" /bin/true


    else


      action "10.0.0.$i is ok" /bin/false


  fi


done


</pre>

<h1><a name="_Toc420786639"></a>6         写一个脚本解决DOS攻击生产案例</h1>

提示:根据web日志或者或者网络连接数,监控当某个IP并发连接数或者短时内PV达到100,即调用防火墙命令封掉对应的IP,监控频率每隔3分钟。防火墙命令为:iptables-A INPUT -s 10.0.1.10 -j DROP。


方法一(注意在函数中,iptables命令要使用全路径)

<pre class="brush:shell">#!/bin/bash


 


count=(`egrep "EST" netstat.log |awk -F "[ :]+"  ‘{print $6}‘|sort -n|uniq -c|awk ‘{print $1}‘`)


ip=(`egrep "EST" netstat.log |awk -F "[ :]+"  ‘{print $6}‘|sort -n|uniq -c|awk ‘{print $2}‘`)


iptables(){


for ((i=0;i&lt;${#count[*]};i++))


do


  if [ ${count[$i]} -gt 10 ] &amp;&amp; [ `/sbin/iptables -L -n|grep "${ip[$i]}"|wc -l` -lt 1 ]


    then


      echo `date` &gt;&gt;/opt/DOS.log


      echo ${count[$i]}  ${ip[$i]} &gt;&gt; /opt/DOS.log


      /sbin/iptables -A INPUT -s ${ip[$i]} -j DROP


  fi


done


}


main(){


while true


do


  iptables


  sleep 180


done


}


 


main


</pre>

方法二:

<pre class="brush:shell">while true


do


  #awk ‘{print $1}‘ access.log|grep -v "^$"|sort|uniq -c &gt;/tmp/tmp.log


  grep EST a.log|awk -F ‘[ :]+‘ ‘{print $6}‘|sort|uniq -c &gt;/tmp/tmp.log


  #netstat -an|grep EST|awk -F ‘[ :]+‘ ‘{print $6}‘|sort|uniq -c &gt;/tmp/tmp.log


  exec &lt;/tmp/tmp.log


  while read line


  do


    ip=`echo $line|awk ‘{print $2}‘`


    count=`echo $line|awk ‘{print $1}‘`


    if [ $count -gt 3 ] &amp;&amp; [ `iptables -L -n|grep "$ip"|wc -l` -lt 1 ]


      then


        iptables -I INPUT -s $ip -j DROP


        echo "$line is dropped" &gt;&gt;/tmp/droplist.log


    fi


  done


  sleep 5


done


</pre>

加入定时任务


*/3 * * * * /bin/sh /server/scripts/ip_drop.sh &gt;/dev/null 2&gt;&amp;1

<h1><a name="_Toc420786640"></a>7         开发mysql多实例启动脚本</h1>

已知mysql多实例启动命令为:mysqld_safe--defaults-file=/data/3306/my.cnf &amp;

停止命令为:mysqladmin -u root -poldboy123 -S /data/3306/mysql.sockshutdown

请完成mysql多实例启动启动脚本的编写

要求:用函数,case语句、if语句等实现。

<pre class="brush:shell">#!/bin/bash


#lixinyu linux


#2015-5-15


# chkconfig: 2345 25 60


# description: mysql start and stop scripts


 


. /etc/init.d/functions


DIR=/data/3306


USER=root


PASSWORD=123456


PORT=3306


 


function mysql_start(){


PID=`lsof -i:$PORT|wc -l`


[ $PID -lt 2 ]&amp;&amp;{


  /usr/local/sbin/mysqld_safe  --defaults-file=$DIR/my.cnf  &gt;/dev/null 2&gt;&amp;1 &amp;


  if [ $? -eq 0 ]


    then


      sleep 3


      action "mysqld is start" /bin/true


    else


      action "mysqld is start" /bin/false


  fi


  return 0


}||{


  action "The mysql is running now" /bin/false


  return 1


  }


}


 


function mysql_stop(){


PID=`lsof -i:$PORT|wc -l`


[ $PID -ge 2 ]&amp;&amp;{


  /usr/local/sbin/mysqladmin -u $USER -p"$PASSWORD" -S $DIR/mysql.sock shutdown  &gt;/dev/null 2&gt;&amp;1 &amp;


  if [ $? -eq 0 ]


    then


      sleep 3


      action "mysqld is stop" /bin/true


    else


      action "mysqld is stop" /bin/false


  fi


  return 0


}||{


  action "The mysql is stoping now" /bin/false


  return 1


  }


}


 


function USAGE(){


echo "USAGE:$0 {start|stop|restart}"


}


[ $# -ne 1 ]&amp;&amp;{


  USAGE


  exit 1


}


case "$1" in


start)


     mysql_start


     ;;


stop)


     mysql_stop


     ;;


restart)


     mysql_stop


     mysql_start


     ;;


*)


     USAGE


esac


</pre>

<h1><a name="_Toc420786641"></a>8         对MySQL数据库进行分库备份</h1>

<pre class="brush:shell">#!/bin/bash


#lixinyu linux


#2015-5-20


 


user=root


password=123456


sock=/data/3306/mysql.sock


MYCMD="mysql -u$user -p$password -S $sock"


MYDUMP="mysqldump  -u$user -p$password -S $sock"


 


for database in `$MYCMD  -e "show databases;"|sed ‘1d‘|egrep -v ‘mysql|_schema‘`


do


  $MYDUMP -B --master-data=2 --events --single-transaction $database|gzip &gt;/opt/${database}_$(date +%F).sql.gz


done


</pre>

<h1><a name="_Toc420786642"></a>9         对MySQL数据库进行分库加分表备份</h1>

<pre class="brush:shell">#!/bin/bash


#lixinyu linux


#2015-5-20


 


user=root


password=123456


sock=/data/3306/mysql.sock


MYCMD="mysql -u$user -p$password -S $sock"


MYDUMP="mysqldump  -u$user -p$password -S $sock"


 


for database in `$MYCMD  -e "show databases;"|sed ‘1d‘|egrep -v "mysql|_schema"`


do


  mkdir /backup/${database} -p


  for table in `$MYCMD -e "show tables from $database"|sed "1d"`


  do


    $MYDUMP $database $table|gzip &gt;/backup/${database}/${database}.${table}_$(date +%F).sql.gz


  done


done


</pre>

<h1><a name="_Toc420786643"></a>10    字符串打印</h1>

<strong>请用至少两种方法实现!</strong>

bash for循环打印下面这句话中字母数不大于6的单词(昆仑万维面试题)。

I am oldboy teacher welcome to oldboy training class.


方法一

<pre class="brush:shell">#!/bin/bash


 


for n in I am oldboy teacher welcome to oldboy training class


do


  if [ ${#n} -le 6 ];then


    echo $n


  fi


done


</pre>

方法二

<pre class="brush:shell">#!/bin/bash


 


chars=(I am oldboy teacher welcome to oldboy training class)


for ((i=0;i&lt;${#chars[*]};i++))


do


  if [ ${#chars[i]} -le 6 ];then


    echo ${chars[i]}


  fi


done


</pre>

<h1><a name="_Toc420786644"></a>11    计算比较</h1>

开发shell脚本分别实现以脚本传参以及read读入的方式比较2个整数大小。以屏幕输出的方式提醒用户比较结果。注意:一共是开发2个脚本。当用脚本传参以及read读入的方式需要对变量是否为数字、并且传参个数做判断。

<pre class="brush:shell">#!/bin/bash


read -t 30 -p "pls input two num:" a b


 


[ ${#a} -eq 0 -o  ${#b} -eq 0 ]&amp;&amp;{


echo "you need input two num"


exit 1


}


 


expr $a + 1 &amp;&gt;/dev/null


RETVAL_A=$?


expr $b + 1 &amp;&gt;/dev/null


RETVAL_B=$?


[ $RETVAL_A -ne 0 -o $RETVAL_B -ne 0 ]&amp;&amp;{


echo "one of your input is not int."


exit 1


}


 


[ $a -gt $b ]&amp;&amp;{


echo "$a&gt;$b"


exit 0


}


 


[ $a -eq $b ]&amp;&amp;{


echo "$a=$b"


exit 0


}


 


[ $a -lt $b ]&amp;&amp;{


echo "$a&lt;$b"


exit 0


}


</pre>

第二个

<pre class="brush:shell">#!/bin/bash


#read -t 30 -p "pls input two num:" a b


 


#[ ${#a} -eq 0 -o  ${#b} -eq 0 ]&amp;&amp;{


# echo "you need input two num"


# exit 1


#}


 


[ $# -ne 2 ]&amp;&amp;{


echo "USAGE:$0 INT1 INT2"


exit 1


}


a=$1


b=$2


 


expr $a + 1 &amp;&gt;/dev/null


RETVAL_A=$?


expr $b + 1 &amp;&gt;/dev/null


RETVAL_B=$?


[ $RETVAL_A -ne 0 -o $RETVAL_B -ne 0 ]&amp;&amp;{


echo "one of your input is not int."


exit 1


}


 


if [ $a -eq $b ]


  then


    echo "$a=$b"


elif [ $a -gt $b ]


  then


    echo "$a&gt;$b"


else


    echo "$a&lt;$b"


fi


</pre>

<h1><a name="_Toc420786645"></a>12    打印菜单(堡垒机)</h1>

打印选择菜单,一键安装Web服务:


[root@oldboyscripts]# sh menu.sh


1.[install lamp]


2.[install lnmp]


3.[exit]


pls input the num you want:


要求:


1、当用户输入1时,输出“startinstalling lamp.”然后执行/server/scripts/lamp.sh,脚本内容输出"lampis installed"后退出脚本;


2、当用户输入2时,输出“startinstalling lnmp.”然后执行/server/scripts/lnmp.sh输出"lnmpis installed"后退出脚本;


3、当输入3时,退出当前菜单及脚本;


4、当输入任何其它字符,给出提示“Input error”后退出脚本。


5、要对执行的脚本进行相关条件判断,例如:脚本是否存在,是否可执行等。


<strong>本题只是一个简单案例,练习cat的使用</strong>

<pre class="brush:shell">#!/bin/bash


 


menu(){


cat &lt;&lt;END


1.[install lamp]


2.[install lnmp]


3.[exit]


pls input the num you want:


END


}


menu


read -t 15 a


[ $a -eq 1 ]&amp;&amp;{


  echo "installing lamp"


  sleep 3


  echo "lamp is installed."


  exit


}


[ $a -eq 2 ]&amp;&amp;{


  echo "installing lnmp"


  sleep 3


  echo "lnmp is installed."


  exit


}


 


[ $a -eq 3 ]&amp;&amp;{


  exit


}


 


[ ! $a -eq 1 -o ! $a -eq 2 -o ! $a -eq 3 ] &amp;&amp;{


  echo "bye"


  exit 1


}


</pre>

<h1><a name="_Toc420786646"></a>13    检测web服务及mysql服务</h1>

1、监控web服务是否正常,不低于3种监控策略。


2、监控db服务是否正常,不低于3种监控策略。

要求间隔1分钟,持续监控。


本题只是给出解决问题的思路,写的比较简单和仓促,不代表生产环境脚本


<strong>检测web</strong>

<pre class="brush:shell">[root@c66-kslx 0502]# cat web_curl.sh


#!/bin/sh


 


while true


do


NGINX_NU=`curl -I -s -w "%{http_code}" -o /dev/null 192.168.235.129`


if [ "${NGINX_NU}" == "200" ]


  then


    echo "nginx server is OK"


  else


    echo "nginx server is not ok"


fi


sleep 1


done


[root@c66-kslx 0502]# cat web_lsof.sh


#!/bin/sh


 


while true


do


  NGINX_NU=`lsof -i:80|grep nginx|wc -l`


  if [ ${NGINX_NU} -ge 2 ]


    then


      echo "nginx server is OK"


    else


      echo "nginx server is not ok"


  fi


  sleep 1


done


[root@c66-kslx 0502]# cat web_nmap.sh


#!/bin/sh


 


while true


do


  NGINX_NU=`nmap 192.168.235.129 -p 80|grep open|wc -l`


  if [ ${NGINX_NU} -eq 1 ]


    then


      echo "nginx server is OK"


    else


      echo "nginx server is not ok"


  fi


  sleep 1


done


[root@c66-kslx 0502]# cat web_ps.sh


#!/bin/sh


 


while true


do


  NGINX_NU=`ps aux |grep nginx|wc -l`


  if [ ${NGINX_NU} -ge 2 ]


    then


      echo "nginx server is OK"


    else


      echo "nginx server is not ok"


  fi


  sleep 1


done


[root@c66-kslx 0502]# cat web_wget.sh


#!/bin/sh


 


while true


do


  wget --spider --timeout=10 --tries=2 192.168.235.129 &gt;/dev/null 2&gt;&amp;1


  if [ $? -eq 0 ]


    then


      echo "nginx server is OK"


    else


      echo "nginx server is not ok"


  fi


  sleep 1


done


</pre>

<strong>检测mysql</strong>

<pre class="brush:shell">[root@c66-kslx 0502]# cat mysql_lsof.sh


#!/bin/sh


 


while true


do


  MYSQL_NU=`lsof -i:3306|wc -l`


  if [ ${MYSQL_NU} -ge 2 ]


    then


      echo "mysql server is OK"


    else


      echo "mysql server is not ok"


  fi


  sleep 1


done


[root@c66-kslx 0502]# cat mysql_netstat.sh


#!/bin/sh


 


while true


do


  MYSQL_NU=`netstat -lutup |grep mysql |wc -l`


  if [ ${MYSQL_NU} -ge 1 ]


    then


      echo "mysql server is OK"


    else


      echo "mysql server is not ok"


  fi


  sleep 1


done


[root@c66-kslx 0502]# cat mysql_ps.sh


#!/bin/sh


 


while true


do


  MYSQL_NU=`ps aux | grep mysql|wc -l`


  if [ ${MYSQL_NU} -ge 2 ]


    then


      echo "mysql server is OK"


    else


      echo "mysql server is not ok"


  fi


  sleep 1


done


[root@c66-kslx 0502]# cat mysql_show.sh


#!/bin/sh


 


while true


do


  mysql -uroot -p"123456" -S /data/3306/mysql.sock -e "show databases;" &gt;/dev/null 2&gt;&amp;1


  if [ $? -eq 0 ]


    then


      echo "mysql server is OK"


    else


      echo "mysql server is not ok"


  fi


  sleep 1


done


</pre>

&nbsp;

<h1><a name="_Toc420786647"></a>14    监控memcached</h1>

监控memcache服务是否正常,模拟用户(web客户端)检测。


使用nc命令加上set/get来模拟检测,以及监控响应时间及命中率。


脚本写的比较屎,像一坨,也是,给出方法

<pre class="brush:shell">#!/bin/sh


 


while true


do


mem=`lsof -i:11211|wc -l`


if [ $mem -gt 1 ]


  then


    printf "set key_test 0 0 4\r\ntest\r\n"|nc 127.0.0.1 11211 &gt;/dev/null 2&gt;&amp;1


    value1=`echo $?`


    printf "get key_test\r\n"|nc 127.0.0.1 11211 &gt;/dev/null 2&gt;&amp;1


    value2=`echo $?`


    printf "delete key_test\r\n"|nc 127.0.0.1 11211 &gt;/dev/null 2&gt;&amp;1


    value3=`echo $?`


    if [ $value1 -eq 0 -a $value2 -eq 0 -a $value3 -eq 0 ]


      then


#       echo "$(date +‘%F %H:%M‘) memcached server is ok" &gt;&gt;/opt/memcached.log


      else


        echo "$(date +‘%F %H:%M‘) memcached server is error"&gt;&gt; /opt/memcached_error1.log


        mail -s "memcached is error" [email protected] &lt;/opt/memcached_error1.log


        exit 1


    fi


  else


    echo "$(date +‘%F %H:%M‘) memcached server not start" &gt;&gt;/opt/memcached_error2.log


    memcached -d -c 10240 -p 11211 -m 16 -P /var/run/memcached.pid -u root


    [ $? -eq 0 ]&amp;&amp;{


      echo "$(date +‘%F %H:%M‘) memcached server start now" &gt;&gt; /opt/memcached_error2.log


    }||{


      echo "$(date +‘%F %H:%M‘) memcached server start filed, pls dispose" &gt;&gt; /opt/memcached_error2.log


      mail -s "memcached start filed" [email protected] &lt;/opt/memcached_error2.log


    exit 1


    }


fi


  sleep 5


done


</pre>

&nbsp;

<h1><a name="_Toc420786648"></a>15    监控web站点目录是否被篡改</h1>

监控web站点目录(/var/html/www)下所有文件是否被恶意篡改(文件内容被改了),如果有就打印改动的文件名(发邮件),定时任务每3分钟执行一次(10分钟时间完成)。


方法一,使用inotify方法,这里不再写脚本,很简单

<pre class="brush:shell">wget http://github.com/downloads/rvoicilas/inotify-tools/inotify-tools-3.14.tar.gz


tar zxf inotify-tools-3.14.tar.gz


cd inotify-tools-3.14


./configure --prefix=/usr/local/inotify-tools-3.14


make &amp;&amp; make install


ln -s /usr/local/inotify-tools-3.14 /usr/local/inotify-tools


/usr/local/inotify-tools-3.14/bin/inotifywait -mrq --timefmt ‘%d/%m/%y %H:%M‘ --format ‘%T %w%f‘ -e create,delete /backup


</pre>

方法二,使用md5校对(感谢张耀同学的思路!)

<pre class="brush:shell">#!/bin/bash


 


DIR=/var/html/www


DBDIR=/server


md5db=$DBDIR/md5.db


newdb=$DBDIR/new.db


diffdb=$DBDIR/diff.db


checklog=/tmp/check.log


 


[ ! -d "$DIR" ]&amp;&amp;{


  echo "This is not web"


  exit 1


}


 


[ ! -d "$DBDIR" ] &amp;&amp; mkdir $DBDIR -p


 


for i in $dm5db $newdb $diffdb $checklog


do


  [ ! -d "$i" ] &amp;&amp; touch $i


done


 


while true


do


  md5sum -c $md5db|grep FAILED &gt;&gt;$checklog 2&gt;&amp;1


  find $DIR -type f &gt;$newdb


  diff $newdb $diffdb &gt;&gt;$checklog 2&gt;&amp;1


  [ -s "$checklog" ] &amp;&amp; \


  #  mail -s "web check $(date +%F)" [email protected] &lt;$checklog


  echo haha


  sleep 300


done


</pre>

<h1><a name="_Toc420786649"></a>16    rsync服务启动脚本</h1>

写网络服务独立进程模式下rsync的系统启动脚本


例如:/etc/init.d/rsyncd{start|stop|restart} 。

要求:

1.要使用系统函数库技巧。

2.要用函数,不能一坨SHI的方式。

3.可被chkconfig管理。


&nbsp;

<pre class="brush:shell">#!/bin/bash


# chkconfig: 2345 31 61


# description: start rsync and stop rsync scripts.


 


#lixinyu linux


#2015-5-15


 


. /etc/init.d/functions


PID_FILE=/var/run/rsyncd.pid


 


rsync_start(){


if [ -f $PID_FILE ]


  then


    action "rsync is running" /bin/false


  else


    rsync --daemon


    if [ $? -eq 0 ]


      then


        sleep 1


        action "rsync is start" /bin/true


      else


        action "rsync is start" /bin/false

 

    fi


fi


}


 


rsync_stop(){


if [ -f $PID_FILE ]


  then


    kill -USR2 `cat $PID_FILE`


    if [ $? -eq 0 ]


      then


        rm -rf $PID_FILE


        sleep 1


        action "rsync is stop" /bin/true


      else


        action "rsync is stop" /bin/false


    fi


  else


    action "rsync is stoping" /bin/false


fi


}


 


USAGE(){


echo "USAGE:$0 {start|stop|restart}"


exit 1


}


 


[ $# -ne 1 ]&amp;&amp;{


USAGE


}


 


case $1 in


start)


     rsync_start


     RETVAL=$?


     ;;


stop)


     rsync_stop


     RETVAL=$?


     ;;


restart)


     rsync_stop


     rsync_start


     RETVAL=$?


     ;;


*)


     USAGE


esac


</pre>

&nbsp;


exit $RETVAL

<h1><a name="_Toc420786650"></a>17    抓阄题</h1>

有N个学生,选出其中三个参加实践


要求:


1、执行脚本后,想去的同学输入英文名字全拼,产生随机数01-99之间的数字,数字越大就去参加项目实践,前面已经抓到的数字,下次不能在出现相同数字。


2、第一个输入名字后,屏幕输出信息,并将名字和数字记录到文件里,<strong>程序不能退出继续等待别的学生输入</strong>。


此题的思路详解如下:


http://www.z-dig.com/the-lottery-of-shell-script-example.html

<pre class="brush:shell">#!/bin/bash


 


file=name_file.db


 


if [ ! -f $file ]


  then


    touch $file


  else


    &gt;$file


fi


 


function ran_num(){


while true


do


  random=$(($RANDOM%99+1))


  if [ -z `egrep $random $file|awk ‘{print $2}‘` ]


    then


      break


  fi


done


}


 


function lot(){


read -p "pls write you name:" name empty


 


[ ${#name} -eq 0 ]&amp;&amp;{


  echo "Please enter one name"


  continue


}


[ ${#empty} -ne 0 ]&amp;&amp;{


  echo "Please enter one name"

 

  continue


}


[ "$name" = "exit" ]&amp;&amp;{


  echo "bey dear"


  exit 0


}


ran_num


if [ -z `egrep $name $file|awk ‘{print $1}‘` ]


  then


    echo "This time obtain random number is:"


    echo "$name $random"


    echo "$name $random" &gt;&gt;$file


  else


    echo "This time obtain random number is:"


    egrep $name $file


fi


}


 


function output(){


  lot


  echo "The random number of the top three:"


  sort -rn -k2 $file|head -3


  [ `cat $file|wc -l` -eq 99 ]&amp;&amp;{


  echo "random number not have,bye dear"


  exit 0


  }


}


function main(){


  while true


  do


    output


  done


}


 

main


</pre>

<h1><a name="_Toc420786651"></a>18    暴力破解密码</h1>

已知下面的字符串是通过RANDOM随机数变量md5sum|cut-c 1-8截取后的结果,请破解这些字符串对应的md5sum前的RANDOM对应数字?


21029299


00205d1c


a3da1677


1f6d12dd


首先要知道RANDOM变量获取的随机数为0-32767之间

<pre class="brush:shell">#!/bin/bash


 


md5=(


21029299


00205d1c


a3da1677


1f6d12dd


)


 


for ((n=0;n&lt;32768;n++))


do


  for ((i=0;i&lt;${#md5[*]};i++))


  do


    if [ "`echo $n|md5sum|cut -c 1-8`" == "${md5[i]}" ]


      then


        echo ${md5[i]}  $n


    fi


  done


done


</pre>

&nbsp;


00205d1c 1346


1f6d12dd 7041


a3da1677 25345


21029299 25667


&nbsp;

<h1><a name="_Toc420786652"></a>19    批量检查多个网站地址是否正常</h1>

要求:shell数组方法实现,检测策略尽量模拟用户访问思路


http://www.etiantian.org


http://www.taobao.com


http://oldboy.blog.51cto.com


http://10.0.0.7


&nbsp;

<pre class="brush:shell">#!/bin/bash


 


. /etc/init.d/functions


url=(


http://www.etiantian.org


http://www.taobao.com


http://oldboy.blog.51cto.com


http://192.168.235.129


http://192.168.235.11


http://192.168.235.12


)


while_url(){


i=0


while [ $i -lt ${#url[*]} ]


do


  wget --spider --timeout=10 --tries=2 ${url[$i]} &amp;&gt;/dev/null


  if [ $? -eq 0 ]


    then


      action "${url[$i]}" /bin/true


    else


      action "${url[$i]}" /bin/false


  fi


  ((i++))


done


}


 


while true


do


  while_url


  sleep 1


done

</pre>

&nbsp;


&nbsp;


&nbsp;


&nbsp;


本文出自 “李新宇” 博客,请务必保留此出处http://496920337.blog.51cto.com/9876010/1656731

shell编程19例

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