shell编程19例
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。
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>
<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 ]&&{
echo "mysql server is stoping"
exit 1
}
}
status_array(){
status=($($MYSQLCMD -e "show slave status\G"|egrep "_Running|Last_Errno|Behind_Master"|awk ‘{print $NF}‘))
}
status_error(){
flag=0
for((i=0;i<${#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 ]&&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>
<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<=10;i++))
do
touch /oldboy/`echo $RANDOM|md5sum|cut -c 1-10`_oldboy.html
done
</pre>
<h1><a name="_Toc420786636"></a>3 批量改名</h1>
将以上文件名中的oldboy全部改成oldgirl(用for循环实现),并且html改成大写。请用两种以上方法实现
方法一
<pre class="brush:shell">#!/bin/bash
cd /oldboy
name=($(ls /oldboy))
for ((i=0;i<${#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 $password >>/opt/user.txt
done
</pre>
<h1><a name="_Toc420786638"></a>5 判断当前局域网存在的主机</h1>
写一个脚本，实现判断10.0.0.0/24网络里，当前在线用户的IP有哪些（方法有很多）
<pre class="brush:shell">#!/bin/bash
. /etc/init.d/functions
for ((i=1;i<=254;i++))
do
ping -c1 10.0.0.$i >/dev/null 2>&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 $2}‘`)
iptables(){
for ((i=0;i<${#count[*]};i++))
do
if [ ${count[$i]} -gt 10 ] && [ `/sbin/iptables -L -n|grep "${ip[$i]}"|wc -l` -lt 1 ]
then
echo `date` >>/opt/DOS.log
echo ${count[$i]} ${ip[$i]} >> /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 >/tmp/tmp.log
grep EST a.log|awk -F ‘[ :]+‘ ‘{print $6}‘|sort|uniq -c >/tmp/tmp.log
#netstat -an|grep EST|awk -F ‘[ :]+‘ ‘{print $6}‘|sort|uniq -c >/tmp/tmp.log
exec </tmp/tmp.log
while read line
do
ip=`echo $line|awk ‘{print $2}‘`
count=`echo $line|awk ‘{print $1}‘`
if [ $count -gt 3 ] && [ `iptables -L -n|grep "$ip"|wc -l` -lt 1 ]
then
iptables -I INPUT -s $ip -j DROP
echo "$line is dropped" >>/tmp/droplist.log
fi
done
sleep 5
done
</pre>
加入定时任务
*/3 * * * * /bin/sh /server/scripts/ip_drop.sh >/dev/null 2>&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 &
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`
[ $PID -lt 2 ]&&{
/usr/local/sbin/mysqld_safe --defaults-file=$DIR/my.cnf >/dev/null 2>&1 &
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 ]&&{
/usr/local/sbin/mysqladmin -u $USER -p"$PASSWORD" -S $DIR/mysql.sock shutdown >/dev/null 2>&1 &
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 ]&&{
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 $database|gzip >/opt/${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 $table|gzip >/backup/${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 $n
fi
done
</pre>
方法二
<pre class="brush:shell">#!/bin/bash
chars=(I am oldboy teacher welcome to oldboy training class)
for ((i=0;i<${#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 ]&&{
echo "you need input two num"
exit 1
}
expr $a + 1 &>/dev/null
RETVAL_A=$?
expr $b + 1 &>/dev/null
RETVAL_B=$?
[ $RETVAL_A -ne 0 -o $RETVAL_B -ne 0 ]&&{
echo "one of your input is not int."
exit 1
}
[ $a -gt $b ]&&{
echo "$a>$b"
exit 0
}
[ $a -eq $b ]&&{
echo "$a=$b"
exit 0
}
[ $a -lt $b ]&&{
echo "$a<$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 ]&&{
# echo "you need input two num"
# exit 1
#}
[ $# -ne 2 ]&&{
echo "USAGE:$0 INT1 INT2"
exit 1
}
a=$1
b=$2
expr $a + 1 &>/dev/null
RETVAL_A=$?
expr $b + 1 &>/dev/null
RETVAL_B=$?
[ $RETVAL_A -ne 0 -o $RETVAL_B -ne 0 ]&&{
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>$b"
else
echo "$a<$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 <<END
1.[install lamp]
2.[install lnmp]
3.[exit]
pls input the num you want:
END
}
menu
read -t 15 a
[ $a -eq 1 ]&&{
echo "installing lamp"
sleep 3
echo "lamp is installed."
exit
}
[ $a -eq 2 ]&&{
echo "installing lnmp"
sleep 3
echo "lnmp is installed."
exit
}
[ $a -eq 3 ]&&{
exit
}
[ ! $a -eq 1 -o ! $a -eq 2 -o ! $a -eq 3 ] &&{
echo "bye"
exit 1
}
</pre>
<h1><a name="_Toc420786646"></a>13 检测web服务及mysql服务</h1>
1、监控web服务是否正常，不低于3种监控策略。
2、监控db服务是否正常，不低于3种监控策略。
要求间隔1分钟，持续监控。
本题只是给出解决问题的思路，写的比较简单和仓促，不代表生产环境脚本
<strong>检测web</strong>
<pre class="brush:shell">[root@c66-kslx 0502]# cat web_curl.sh
#!/bin/sh
while true
do
NGINX_NU=`curl -I -s -w "%{http_code}" -o /dev/null 192.168.235.129`
if [ "${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 >/dev/null 2>&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;" >/dev/null 2>&1
if [ $? -eq 0 ]
then
echo "mysql server is OK"
else
echo "mysql server is not ok"
fi
sleep 1
done
</pre>
<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，这里只给出方法
<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 >/dev/null 2>&1
value1=`echo $?`
printf "get key_test\r\n"|nc 127.0.0.1 11211 >/dev/null 2>&1
value2=`echo $?`
printf "delete key_test\r\n"|nc 127.0.0.1 11211 >/dev/null 2>&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" >>/opt/memcached.log
else
echo "$(date +‘%F %H:%M‘) memcached server is error">> /opt/memcached_error1.log
mail -s "memcached is error" [email protected] </opt/memcached_error1.log
exit 1
fi
else
echo "$(date +‘%F %H:%M‘) memcached server not start" >>/opt/memcached_error2.log
memcached -d -c 10240 -p 11211 -m 16 -P /var/run/memcached.pid -u root
[ $? -eq 0 ]&&{
echo "$(date +‘%F %H:%M‘) memcached server start now" >> /opt/memcached_error2.log
}||{
echo "$(date +‘%F %H:%M‘) memcached server start filed, pls dispose" >> /opt/memcached_error2.log
mail -s "memcached start filed" [email protected] </opt/memcached_error2.log
exit 1
}
fi
sleep 5
done
</pre>
<h1><a name="_Toc420786648"></a>15 监控web站点目录是否被篡改</h1>
监控web站点目录（/var/html/www）下所有文件是否被恶意篡改（文件内容被改了），如果有就打印改动的文件名（发邮件），定时任务每3分钟执行一次(10分钟时间完成)。
方法一，使用inotify方法，这里不再写脚本，很简单
<pre class="brush:shell">wget http://github.com/downloads/rvoicilas/inotify-tools/inotify-tools-3.14.tar.gz
tar zxf inotify-tools-3.14.tar.gz
cd inotify-tools-3.14
./configure --prefix=/usr/local/inotify-tools-3.14
make && make install
ln -s /usr/local/inotify-tools-3.14 /usr/local/inotify-tools
/usr/local/inotify-tools-3.14/bin/inotifywait -mrq --timefmt ‘%d/%m/%y %H:%M‘ --format ‘%T %w%f‘ -e create,delete /backup
</pre>
方法二，使用md5校对（注：感谢张耀同学的思路分享！）
<pre class="brush:shell">#!/bin/bash
DIR=/var/html/www
DBDIR=/server
md5db=$DBDIR/md5.db
newdb=$DBDIR/new.db
diffdb=$DBDIR/diff.db
checklog=/tmp/check.log
[ ! -d "$DIR" ]&&{
echo "This is not web"
exit 1
}
[ ! -d "$DBDIR" ] && mkdir $DBDIR -p
for i in $dm5db $newdb $diffdb $checklog
do
[ ! -d "$i" ] && touch $i
done
while true
do
md5sum -c $md5db|grep FAILED >>$checklog 2>&1
find $DIR -type f >$newdb
diff $newdb $diffdb >>$checklog 2>&1
[ -s "$checklog" ] && \
# mail -s "web check $(date +%F)" [email protected] <$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。
<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 ]&&{
USAGE
}
case $1 in
start)
rsync_start
RETVAL=$?
;;
stop)
rsync_stop
RETVAL=$?
;;
restart)
rsync_stop
rsync_start
RETVAL=$?
;;
*)
USAGE
esac
exit $RETVAL
</pre>
<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 $file
else
>$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 ]&&{
echo "Please enter one name"
continue
}
[ ${#empty} -ne 0 ]&&{
echo "Please enter one name"
continue
}
[ "$name" = "exit" ]&&{
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 $random" >>$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 $file|wc -l` -eq 99 ]&&{
echo "random number not have,bye dear"
exit 0
}
}
function main(){
while true
do
output
done
}
main
</pre>
<h1><a name="_Toc420786651"></a>18 暴力破解密码</h1>
已知下面的字符串是通过RANDOM随机数变量md5sum|cut-c 1-8截取后的结果，请破解这些字符串对应的md5sum前的RANDOM对应数字？
21029299
00205d1c
a3da1677
1f6d12dd
首先要知道RANDOM变量获取的随机数为0-32767之间
<pre class="brush:shell">#!/bin/bash
md5=(
21029299
00205d1c
a3da1677
1f6d12dd
)
for ((n=0;n<32768;n++))
do
for ((i=0;i<${#md5[*]};i++))
do
if [ "`echo $n|md5sum|cut -c 1-8`" == "${md5[i]}" ]
then
echo ${md5[i]} $n
fi
done
done
</pre>
00205d1c 1346
1f6d12dd 7041
a3da1677 25345
21029299 25667
<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
<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]} &>/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>
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