shell企业面试题
shell企业面试题
1.利用bash for循环打印下面这句话中字母数不大于6的单词
I am oldboy teacher welcome to oldboy training class
[root@ci-node1 mst]# cat 1.sh
#!/bin/bash
##############################################################
# File Name: 1.sh
# Version: V1.0
# Author: liu
# Organization:
# Created Time : 2019-04-15 22:28:35
# Description:
##############################################################
#数组实现
arrary=(I am oldboy teacher welcome to oldboy training class)
for ((i=0;i<${#arrary[*]};i++))
do
if [ ${#arrary[i]} -le 6 ]
then
echo ${arrary[i]}
fi
done
echo ---------------------------
#使用for循环实现
for i in I am oldboy teacher welcome to oldboy training class
do
if [ ${#i} -le 6 ]
then
echo $i
fi
done
#使用awk循环实现
[root@ci-node1 mst]# chars="I am oldboy teacher welcome to oldboy training class"
[root@ci-node1 mst]# echo $chars
I am oldboy teacher welcome to oldboy training class
[root@ci-node1 mst]# echo $chars|awk '{for(i=0;i<=NF;i++) if(length($i)<=6)print $i}'
2. 批量随机生成字符文件案例
使用for循环在/oldboy目录下批量创建10个html文件，其中每个文件需要包含10个随机小写字每加固定oldboy
随机生成字符串的方法
1.echo $RANDOM 取值范围是0-32767
2.openssl rand -base64 100
3.date +%s%N
4.head /dev/urandom |cksum
5.uuidgen
6.cat /proc/sys/kernel/random/uuid
7.mkpasswd(需先安装yum -y expect)
[root@ci-node1 mst]# mkpasswd -l 20 -d 10 -c 5 -C 3 -s 2
-l:指定长度
-d:指定数字
-c：指定小写
-C：指定大写
-s:指定特殊符号
cat: 1.: No such file or directory
[root@web01 scripts]# cat 1.sh
#!/bin/bash
##############################################################
# File Name: 1.sh
# Version: V1.0
# Author: liu
# Organization:
# Created Time : 2019-04-15 19:04:12
# Description:
##############################################################
[ -d /oldboy ] || mkdir /oldboy
for name in {1..10}
do
cd /oldboy
rand=`echo "$RANDOM"|md5sum |tr "[0-9]" "[a-z]"|cut -c 2-10`
touch ${rand}_oldboy.html
done
echo "文件已创建完成"
2.批量改名特殊案例
将上面题1中的结果文件名中的oldboy字符串全部改成oldgirl(最好使用for循环实现)，并且将扩展名改为HTML大写
方法一：使用awk进行批量改名
[root@web01 scripts]# ls /oldboy/*.html|awk -F "oldboy.html" '{print "mv",$0,$1".oldgril.HTML"}'|bash
方法二：使用for循环
[root@web01 scripts]# cat 2.sh
#!/bin/bash
##############################################################
# File Name: 2.sh
# Version: V1.0
# Author: liu
# Organization:
# Created Time : 2019-04-15 19:55:32
# Description:
##############################################################
file_path=`ls /oldboy`
for i in $file_path
do
cd /oldboy
mv $i `echo ${i/oldgril.HTML/oldboy.html}`
done
方法三：使用rename
语法：rename 找查的内容 替换的内空 文件名
[root@web01 oldboy]# rename ".oldgril.HTML" "oldboy.html" *.HTML
3.批量创建特殊要求用户案例
批量创建10个系统账号oldboy01-oldboy10，并设置密码为随机数，要求字符和数字混合）
[root@web01 scripts]# vim useradd.sh
#!/bin/bash
##############################################################
# File Name: useradd.sh
# Version: V1.0
# Author: liu
# Organization:
# Created Time : 2019-04-16 09:29:02
# Description:
##############################################################
. /etc/init.d/functions
#方法一:使用拼接方式创建
#user=`seq -w 11 15`
#for i in $user
#do
# passwd=`openssl rand -base64 5`
# useradd oldboy$i
# echo $passwd|passwd --stdin oldboy$i
# echo -e "oldboy$i\t$passwd" >> /tmp/useradd.log
#done
#方法二：使用chpasswd方法创建,此方法只能使用这一种格式：用户名:密码
for i in {22..25}
do
passwd=`openssl rand -base64 5`
grep "oldboy$i" /etc/passwd &>/dev/null
if [ $? -ne 0 ]
then
useradd oldboy$i &>/dev/null
echo "oldboy$i:$passwd" >> /tmp/user.log
action "oldboy$i is successful" /bin/true
else
action "oldboy$i is exists" /bin/false
fi
done
4.扫描网络内存活主机案例
写一个shell脚本，判断10.0.0.0/24网段中，当前在线的ip的址有多少
方法一：使用脚步进行检测
[root@web01 scripts]# cat ping.sh
#!/bin/bash
##############################################################
# File Name: ping.sh
# Version: V1.0
# Author: liu
# Organization:
# Created Time : 2019-04-16 11:18:42
# Description:
##############################################################
. /etc/init.d/functions
for i in {1..254}
do
{
if `ping -c 1 -w 3 172.16.1.$i >&/dev/null`
then
echo "172.16.1.$i is up"
else
echo "172.16.1.$i is down"
fi
} &
done
方法二：使用命令
[root@web01 scripts]# nmap -sP 10.0.0.0/24|awk '/Nmap scan report for/{print $NF}'
5.mysql数据库分库备份
实现对mysql数据库进行分库备份，使用脚本
使用命令查询数据库信息
mysql -uroot -poldboy -e "show database;"
[root@web01 scripts]# cat mysql.sh
#!/bin/bash
##############################################################
# File Name: mysql.sh
# Version: V1.0
# Author: liu
# Organization:
# Created Time : 2019-04-16 14:43:23
# Description:
##############################################################
. /etc/init.d/functions
user="root"
password="oldboy"
path=/backup/mysql
mysql_name=`mysql -u$user -p$password -e "show databases;" 2>/dev/null|grep -v _schema|sed 1d`
[ -d $path ] || mkdir -p $path
for name in $mysql_name
do
mysqldump -u$user -p$password -B $name &>/dev/null|gzip >$path/${name}_$(date +%F).sql.gz
if [ $? -eq 0 ]
then
action "$name backcup is success" /bin/true
else
action "$name backup is fail" /bin/false
fi
done
6.mysql数库分库分表备份
如何实现对mysql数据库进行分库加分表备份
使用命令查询分表信息
[root@web01 scripts]# mysql -uroot -poldboy -e "show tables from wordpress;"
前提：需在/etc/my.cnf配置文件中添加mysql用户名与密码
[client]
user="root"
password="oldboy"
[root@web01 scripts]# cat mysql_1.sh
#!/bin/bash
##############################################################
# File Name: mysql.sh
# Version: V1.0
# Author: liu
# Organization:
# Created Time : 2019-04-16 14:43:23
# Description:
##############################################################
. /etc/init.d/functions
path=/backup/mysql
mysql_name=`mysql -e "show databases;" |grep -v _schema|sed 1d`
[ -d $path ] || mkdir -p $path
for name in $mysql_name
do
mysql_table=`mysql -e "show tables from $name;"|sed 1d`
for tname in ${mysql_table}
do
if [ "$name" = "mysql" ]
then
mysqldump --skip-lock-tables $name $tname |gzip >$path/${name}_${tname}_$(date +%F).s
ql.gz if [ $? -eq 0 ]
then
action "$name backcup is success" /bin/true
else
action "$name backup is fail" /bin/false
fi
else
mysqldump $name $tname |gzip >$path/${name}_${tname}_$(date +%F).sql.gz
if [ $? -eq 0 ]
then
action "$name backcup is success" /bin/true
else
action "$name backup is fail" /bin/false
fi
fi
done
done
7.SSH免密钥批量分发文件专业脚本案例
有3台机器，m01,backup,nfs01,采用ssh免密钥实现从m01到其它两台机器无密码登陆后，批量分发任意文件到其它两台机器的任意目录下
#分发免密钥脚本
[root@m01 scripts]# cat ansible.sh
#!/bin/bash
ip='7 31'
key='dsa'
if [ -f "/root/.ssh/id_$key" ]
then
rm -f /root/.ssh/id_$key
fi
ssh-keygen -t $key -f /root/.ssh/id_dsa -N ""
for ip in $ip
do
sshpass -pliuyang ssh-copy-id -i /root/.ssh/id_$key.pub "-o StrictHostKeyChecking=no 172.16.1.$ip -
p10000"done
分发脚本
[root@m01 scripts]# cat 2.sh
#!/bin/bash
. /etc/init.d/functions
ip='7 31'
if [ $# -ne 2 ]
then
echo "Uasge:$0 localdir remotedir"
exit 1
fi
for i in $ip
do
echo =====172.16.1.$i========
scp -rP10000 $1 172.16.1.$i:$2 &>/dev/null
if [ $? -eq 0 ]
then
action "$1 is successful" /bin/true
else
action "$1 is fail" /bin/false
fi
done
8.破解RANDOM随机数案例
已知下面的字符串是RANDOM通过md5sum后，再截取一部分连续字符串的结果，请破解这些字符串对应的使用的md5sum处理前RANDOM的数字
21029299
00205d1c
a3da1677
1f6d12dd
890684b
[root@web01 scripts]# cat md5.sh
#!/bin/bash
##############################################################
# File Name: md5.sh
# Version: V1.0
# Author: liu
# Organization:
# Created Time : 2019-04-16 16:43:18
# Description:
##############################################################
md5=(
21029299
00205d1c
a3da1677
1f6d12dd
890684b
)
generate_md5(){
for num in {0..32767}
do
echo -e "$num\t `echo $num|md5sum`" >> /tmp/md5.log
done
}
check_md5(){
for i in ${md5[*]}
do
if [ `grep $i /tmp/md5.log|wc -l` -eq 1 ]
then
grep $i /tmp/md5.log
fi
done
}
main(){
path=/tmp/md5.log
if [ ! -s "$path" ]
then
generate_md5
fi
echo ======数据解密码中======
check_md5
echo ======数据解密完成======
}
main
9.批量检查多个网站地址是否正常
要求：
1.使用shell数组方法实现，检测策略尽量模用户访问
2.每10秒钟做一次检测，无法访问的输出报警
3.等检测的地址如下
http://blog.oldboyedu.com
http://blog.etiantian.org
http://10.0.0.7
[root@web01 scripts]# cat web.sh
#!/bin/bash
##############################################################
# File Name: web.sh
# Version: V1.0
# Author: liu
# Organization:
# Created Time : 2019-04-16 18:03:53
# Description:
##############################################################
. /etc/init.d/functions
url=(
http://blog.oldboyedu.com
http://blog.etiantian.org
http://10.0.0.7
http://172.16.1.7
http://www.baidu.com
)
check_url(){
for ((i=0;i<${#url[*]};i++))
do
wget --spider -T 5 -t 2 -q -o /dev/null ${url[$i]}
if [ $? -eq 0 ]
then
action "${url[$i]} is runing" /bin/true
else
action "${url[$i]} in not runing" /bin/false
fi
done
}
main(){
while true
do
echo -------------
check_url
sleep 10
done
}
main
10.解决DOS攻击生产案例
请根据web日志或者网络连接数，监控某一个IP并发连接数或都 短时间pv达到100，即调用防火墙命令封掉对应的IP，防火墙命令为iptables -I INPUT -s ip地址 -j DROP
web访问日志监控脚本：
[root@web01 scripts]# cat iptables.sh
#!/bin/bash ##############################################################
# File Name: iptables.sh
# Version: V1.0
# Author: liu
# Organization:
# Created Time : 2019-04-16 19:52:29
# Description:
##############################################################
path=/server/scripts/access_2010-12-8.log
while true
do
awk '{print $1}' ${path}|sort -nr|uniq -c >/tmp/web.log
while read line
do
count=`echo $line|awk '{print $1}'`
ip=`echo $line|awk '{print $2}'`
drop_ip=`iptables -nL|awk '/DROP/{print $4}'|grep "$ip"`
if [ $count -ge 50 ]
then
if [ "$ip" != "$drop_ip" ]
then
iptables -I INPUT -s $ip -j DROP
fi
fi
done</tmp/web.log
done
根据连接数禁止ip访问
path=/server/scripts/netstat.log
awk -F "[ :]+" '/ESTABLISHED/{s[$6]++}END{for(k in s) print s[k],k}' $path|sort -nr >/tmp/web01.log
while read line
do
count=`echo $line|awk '{print $1}'`
ip=`echo $line|awk '{print $2}'`
drop_ip=`iptables -nL|awk '/DROP/{print $4}'|grep "$ip"`
if [ $count -ge 100 -a "$ip" != "$drop_ip" ]
then
iptables -I INPUT -s $ip -j DROP
fi
done</tmp/web01.log
11.开发mysql服务启动脚本
[root@web01 scripts]# cat mysqld.sh
#!/bin/bash
##############################################################
# File Name: mysqld.sh
# Version: V1.0
# Author: liu
# Organization:
# Created Time : 2019-04-17 11:37:51
# Description:
##############################################################
. /etc/init.d/functions
mysql_pid=/application/mysql/data/`uname -n`.pid
lockfile=/var/lock/subsys/mysqld
datadir=/application/mysql/data
mysqld_safe=/application/mysql/bin/mysqld_safe
start(){
/bin/sh $mysqld_safe --datadir=$datadir --pid-file=$mysql_pid &>/dev/null &
retval=$?
sleep 2
if [ $retval -eq 0 ]
then
action "Mysql start is successful..." /bin/true
touch $lockfile
return $retval
else
action "Mysql start is fail... " /bin/false
return $retval
fi
}
stop(){
if [ -s "$mysql_pid" ]
then
mysql_pid=`cat $mysql_pid`
if (kill -0 $mysql_pid &>/dev/null)
then
kill $mysql_pid
retval=$?
sleep 2
if [ $retval -eq 0 ]
then
action "Mysql stop is successful" /bin/true
rm -f $lockfile
return $retval
else
action "Mysql stop is fail" /bin/false
return $retval
fi
fi
fi
}
case $1 in
start)
start
retval=$?
;;
stop)
stop
retval=$?
;;
restart)
stop
retval=$?
sleep 2
start
retval=$?
;;
*)
echo "Usage:$0{start|stop|restart|}"
esac
exit $retval
12.单词及字母去重排序案例
用shell处理以下内容
1.按单词出现频率降序排序
2.按字母现现频率降序排序
the squid project provides a number of resources to assist users design,implement and support squid installations. Please browse the documentation and support sections for more infomation
1.按单词出现频率降序排序
方法一：
cat 12.log|tr " , ." "\n"|sort|uniq -c|sort -nr
方法二：
cat 12.log|tr " .," "\n"|awk '{s[$1]++}END{for(k in s) print s[k],k}'|sort -nr
方法三：RS表示分割符
awk 'BEGIN{RS="[ ,.]"}{s[$1]++}END{for(k in s) print s[k],k}' 12.log |sort -nr
2.按字母现现频率降序排序
方法一：
grep -o "[a-z]" 12.log |sort|uniq -c|sort -nr
方法二：
grep -o "[a-z]" 12.log |awk '{s[$1]++}END{for(k in s) print s[k],k}' | sort -nr
方法三：
sed "s#[ ,\.]##g" 12.log|awk -F "" '{for(i=1;i<NF;i++)s[$i]++}END{for(k in s)print s[k],k}'|sort -nr
