@老男孩Shell企业面试题

shell
2016年9月7日
本文来自于老男孩教育,未经本人同意，禁止转载！否则追究法律责任。
原文：http://oldboy.blog.51cto.com/2561410/1632876

企业面试题1：

　　（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）

[root@oldboy~]# mysql -uroot -p'oldboy' -S /data/3307/mysql.sock -e "show slavestatus\G;"
*************************** 1. row ***************************
               Slave_IO_State:Waiting for master to send event
                  Master_Host:10.0.0.179   #当前的mysql master服务器主机
                  Master_User: rep
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File:mysql-bin.000013
         Read_Master_Log_Pos: 502547
               Relay_Log_File:relay-bin.000013
                Relay_Log_Pos:251
        Relay_Master_Log_File:mysql-bin.000013
             Slave_IO_Running:Yes
           Slave_SQL_Running: Yes
              Replicate_Do_DB:
         Replicate_Ignore_DB: mysql
          Replicate_Do_Table:
      Replicate_Ignore_Table:
     Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
                   Last_Errno: 0
                   Last_Error:
                 Skip_Counter: 0
         Exec_Master_Log_Pos: 502547
              Relay_Log_Space:502986
              Until_Condition:None
               Until_Log_File:
                Until_Log_Pos: 0
          Master_SSL_Allowed: No
          Master_SSL_CA_File:
          Master_SSL_CA_Path:
              Master_SSL_Cert:
           Master_SSL_Cipher:
               Master_SSL_Key:
       Seconds_Behind_Master: 0   #和主库比同步延迟的秒数，这个参数很重要
Master_SSL_Verify_Server_Cert: No
                Last_IO_Errno: 0
                Last_IO_Error:
               Last_SQL_Errno: 0
               Last_SQL_Error:

本脚本由李佳豪同学分享

[root@db02 tmp]# cat MySQL主从监控.sh
#!/bin/bash
Mysql="mysql -uroot -poldboy123 -S /data/3307/mysql.sock"
L_aaa(){
Status=`$Mysql -e "show slave status\G" | grep -E "_Running: Yes|Seconds_Behind_Master: [0-2]" | wc -l`
Code=`$Mysql -e "show slave status\G" | awk '/Last_SQL_Errno:/{print $2}'`
}
L_Status(){
  [ $Status -ne 3 ] && {
    return 1
  } || {
    return 0
  }
}
S_Code=(
1158
1159
1008
1007
1062
)
L_Skip(){
  [ $Code -eq 0 ] && return 0
  for i in ${S_Code[*]}
    do
      [ $Code -eq $i ] && {
        $Mysql -e "stop slave;set global sql_slave_skip_counter = 1;start slave;" && \
        return 0
      }
  done
  return 1
}
main(){
while true
   do
      L_aaa
      L_Skip
      Error1=$?
      L_Status
      Error2=$?
      [ $Error1 -eq 1 -o $Error2 -eq 1 ] && echo "Error"
done
}
main

企业面试题2：

　　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：

[root@oldboy oldboy]# sh /server/scripts/oldboy.sh
[root@oldboy oldboy]# ls
coaolvajcq_oldboy.html  qnvuxvicni_oldboy.html  vioesjmcbu_oldboy.html
gmkhrancxh_oldboy.html  tmdjormaxr_oldboy.html  wzewnojiwe_oldboy.html
jdxexendbe_oldboy.html  ugaywanjlm_oldboy.html  xzzruhdzda_oldboy.html
qcawgsrtkp_oldboy.html  vfrphtqjpc_oldboy.html

脚本如下：

[root@db02 ~]# sh html.sh
[root@db02 ~]# ls /oldboy/
aebccciiaj_oldboy.html  fffabecgbc_oldboy.html
afffebcchb_oldboy.html  ffghcffegb_oldboy.html
dbccddabbj_oldboy.html  hffbhfgdff_oldboy.html
ehbdaedach_oldboy.html  jadafhbaaf_oldboy.html
fbaacihehi_oldboy.html  jgfebjbebd_oldboy.html
[root@db02 ~]# cat html.sh
#!/bin/bash
. /etc/init.d/functions
[ -d /oldboy ]|| mkdir -p /oldboy
cd /oldboy
for i in `seq 10`
do
    touch `echo $RANDOM|md5sum|cut -c 1-10|tr "[0-9]" "[a-z]"`_oldboy.html
done

企业面试题3：

请用至少两种方法实现！
　　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。
第一种方法：

[root@db02 ~]# sh html1.sh
[root@db02 ~]# ll /oldboy/
total 0
-rw-r--r-- 1 root root 0 Jul 20 20:45 aebccciiaj_oldboy.HTML
-rw-r--r-- 1 root root 0 Jul 20 20:45 afffebcchb_oldboy.HTML
-rw-r--r-- 1 root root 0 Jul 20 20:45 dbccddabbj_oldboy.HTML
-rw-r--r-- 1 root root 0 Jul 20 20:45 ehbdaedach_oldboy.HTML
-rw-r--r-- 1 root root 0 Jul 20 20:45 fbaacihehi_oldboy.HTML
-rw-r--r-- 1 root root 0 Jul 20 20:45 fffabecgbc_oldboy.HTML
-rw-r--r-- 1 root root 0 Jul 20 20:45 ffghcffegb_oldboy.HTML
-rw-r--r-- 1 root root 0 Jul 20 20:45 hffbhfgdff_oldboy.HTML
-rw-r--r-- 1 root root 0 Jul 20 20:45 jadafhbaaf_oldboy.HTML
-rw-r--r-- 1 root root 0 Jul 20 20:45 jgfebjbebd_oldboy.HTML
[root@db02 ~]# cat html1.sh
#!/bin/bash
cd /oldboy
for i in `cd /oldboy`
do
   rename "oldboy" "oldgirl" *.html|rename "html" "HTML" *.html
done

第二种方法：

[root@db02 ~]# sh html2.sh
[root@db02 ~]# ll /oldboy/
total 0
-rw-r--r-- 1 root root 0 Jul 20 20:45 aebccciiaj_oldgirl.HTML
-rw-r--r-- 1 root root 0 Jul 20 20:45 afffebcchb_oldgirl.HTML
-rw-r--r-- 1 root root 0 Jul 20 20:45 dbccddabbj_oldgirl.HTML
-rw-r--r-- 1 root root 0 Jul 20 20:45 ehbdaedach_oldgirl.HTML
-rw-r--r-- 1 root root 0 Jul 20 20:45 fbaacihehi_oldgirl.HTML
-rw-r--r-- 1 root root 0 Jul 20 20:45 fffabecgbc_oldgirl.HTML
-rw-r--r-- 1 root root 0 Jul 20 20:45 ffghcffegb_oldgirl.HTML
-rw-r--r-- 1 root root 0 Jul 20 20:45 hffbhfgdff_oldgirl.HTML
-rw-r--r-- 1 root root 0 Jul 20 20:45 jadafhbaaf_oldgirl.HTML
-rw-r--r-- 1 root root 0 Jul 20 20:45 jgfebjbebd_oldgirl.HTML
[root@db02 ~]# cat html2.sh
#!/bin/bash
cd /oldboy
for i in `ls *.HTML`
do
mv $i `echo $i|sed -e 's#oldboy#oldgirl#g;s#html#HTML#g'`
done

补充：QQ 1163718639

[root@db01 shell30]# cat 3.sh 
#!/bin/bash 
for i in /oldboy/* do rename oldboy. oldgir. $i|echo oldgirlok done for x in /oldboy/* do rename html HTML $x|echo htmlok done 
[root@db01 shell30]#

企业面试题4：

　　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）。

[root@db02 tmp]# cat useradd.sh
#!/bin/bash
[ $UID -ne 0 ]&& echo "only root run"&&exit 1
[ -f /etc/init.d/functions ]&& . /etc/init.d/functions
isexist() {
  result=$(grep -w "^$1" /etc/passwd|wc -l)
  if [ $result -ne 0  ];then
    echo "user $1 is exist!!"
    ret 1 "create user is  "
    continue
  fi
}
ret() {
  if [ $1 -eq 0 ];then
    action "$2" /bin/true
  else
    action "$2" /bin/false
  fi
}
create() {
  for i in $(seq -w 10)
  do
    user="oldboy$i"
    isexist $user
    pass=$(cat /proc/sys/kernel/random/uuid|md5sum|cut -c 1-10)
    useradd $user&&echo $pass|passwd --stdin $user &>/dev/null
    ret $? "crate user $user"
    echo "$user $pass" >> /tmp/user.list
  done
}
main() {
  create
}
main

企业面试题5：

　　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）
　　本脚本由刘沈晨分享
注意：此脚本使用nmap，如果没有需要使用yum -y install nmap

[root@db02 scripts]# cat test_5.sh
#!/bin/sh
#
[ -f /etc/init.d/functions ] && . /etc/init.d/functions
function IP_count(){
  for n in 10.0.0.{0..255}
   do
    IP_check=`nmap -sP $n|grep "Host is up"|wc -l`
    if [ ${IP_check} -eq 1 ];then
      action "$n" /bin/true
      let i+=1
    fi
  done
}
function main(){
  IP_count
  echo "The total number of online IP Addresses is " $i
}
main

企业实战题6：

　　写一个脚本解决DOS攻击生产案例
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 -I INPUT -s 10.0.1.10 -j DROP。
　　本脚本使用测试文件进行编写：模拟文件下载链接：http://pan.baidu.com/s/1gfqeHaz 密码：3usn

[root@db02 scripts]# cat test_6.sh
#!/bin/sh
#
[ -f /etc/init.d/functions ] && . /etc/init.d/functions
IP_file="/server/scripts/ddos.txt"
IP_filter_command="iptables -I INPUT -j DROP -s"
IP_recover_command="iptables -D INPUT -j DROP -s"
function IP_check(){
  grep "EST"  ${IP_file}|awk -F "[ |:]+" '{print $6}'|sort |uniq -c|sort -rn -k1 > /server/scripts/ip.txt
}
function IP_filter(){
   exec < /server/scripts/ip.txt
   while read line
   do
     IP_count=`echo $line|awk '{print $1}'`
     IP=`echo $line|awk '{print $2}'`
     IP_fil=`iptables -L -n|grep "\b${IP}\b"|wc -l`
     if [ ${IP_count} -gt 25 -a ${IP_fil} -eq 0 ];then
        ${IP_filter_command} ${IP}
        echo "${IP}" >> /server/scripts/ip_filtered.txt
        action "Filter ${IP}" /bin/true
     fi
   done
}
function IP_recover(){
   exec < /server/scripts/ip.txt
   while read line
   do
     IP_count=`echo $line|awk '{print $1}'`
     IP=`echo $line|awk '{print $2}'`
     IP_fil=`iptables -L -n|grep "\b${IP}\b"|wc -l`
     if [ ${IP_count} -le 25 -a ${IP_fil} -eq 1 ];then
        ${IP_recover_command} ${IP}
        echo "${IP}" >> /server/scripts/ip_filtered.txt
        action "Recover ${IP}" /bin/true
     fi
   done
}
function main(){
    case "$1" in
      filter)
      IP_check
      echo "$(date +%F-%H:%M:%S) filtered by $(whoami)" >> /server/scripts/ip_filtered.txt
      IP_filter
      ;;
      recover)
      IP_check
      echo "$(date +%F-%H:%M:%S) recovered by $(whoami)" >> /server/scripts/ip_filtered.txt
      IP_recover
      ;;
      *)
      echo "USAGE:$0 {filter|recover}"
      exit 1
    esac
}
main $*

企业实战题7：

　　开发mysql多实例启动脚本：
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

1.第一种方法：比较简单，适用于一台MySQL服务器上
[root@db02 mysql]# cat mysql.sh
#!/bin/bash
###########################
#I am YuhongCong
#qq:604419314
##########################
[ -f /etc/init.d/functions ]&& . /etc/init.d/functions
#config
prot=3306
mysql_user=root
mysql_paswd=123456
Path=/data/3306/
mysql_start(){
  if [ -f ${Path}mysqld.pid ];then
    echo "MySQL is running"
    exit 1
  else
    mysqld_safe --defaults-file=${Path}my.cnf &>/dev/null &
    if [ $? -eq 0 ];then
    action "MySQL is starting" /bin/true
    else
    action "MySQL no start" /bin/false
    fi
  fi
}
mysql_stop(){
  if [ ! -f ${Path}mysqld.pid ];then
    echo "Mysql not running"
  else
    mysqladmin -u ${mysql_user} -p${mysql_paswd} -S ${Path}mysql.sock shutdown
    if [ $? -eq 0 ];then
    action "mysql is stop" /bin/true
    else
    action "mysql no stop" /bin/false
    fi
  fi
}
case "$1" in
start)
  mysql_start
    ;;
stop)
  mysql_stop
    ;;
restart)
  mysql_stop
  sleep 3
  mysql_start
    ;;
*)
  echo "Please input {start|stop|restart}"
    ;;
esac

第二种方法：应强哥及李啸宇、大欣等要求进行改版。
　　适用于管理多实例启动的脚本

[root@db02 tmp]# cat mysqlgood.sh
#!/bin/bash
##################
#I am yuhongcong
#qq:604419314
#################
[ -f /etc/init.d/functions ]&& . /etc/init.d/functions
prot=3306
mysql_user=root
mysql_paswd=123456
Path=/data/3306/
#############################################
cat <<END
############################
#    3306
#    3307
#    exit
###########################
END
read -p  "Please input {3306|3307}" a
mysql1_start(){
  if [ -f ${Path}mysqld.pid ];then
    echo "MySQL is runningx"
  else
    mysqld_safe --defaults-file=${Path}my.cnf &>/dev/null &
    if [ $? -eq 0 ];then
      action "mysql 3306 is starting" /bin/true
    else
      action "mysql 3306 not start" /bin/false
    fi
  fi
}
mysql1_stop(){
  if [ ! -f ${Path}mysqld.pid ];then
    echo "mysql 3306 not running"
  else
    mysqladmin -u ${mysql_user} -p${mysql_paswd} -S /data/3306/mysql.sock shutdown 
     if [ $? -eq 0 ];then
    action "mysql 3306 is stopping" /bin/true
     else
    action "mysql 3306 no stop" /bin/false
     fi
  fi
}
mysql2_start(){
  if [ -f /data/3307/mysqld.pid ];then
    echo "MySQL 3307 is runningx"
  else
    mysqld_safe --defaults-file=/data/3307/my.cnf &>/dev/null &
    if [ $? -eq 0 ];then
      action "mysql 3307 is starting" /bin/true
    else
      action "mysql 3307 not start" /bin/false
    fi
  fi
}
mysql2_stop(){
  if [ ! -f /data/3307/mysqld.pid ];then
    echo "mysql 3307 not running"
  else
    mysqladmin -u ${mysql_user} -p${mysql_paswd} -S /data/3307/mysql.sock shutdown 
     if [ $? -eq 0 ];then
    action "mysql 3307 is stopping" /bin/true
     else
    action "mysql 3307 no stop" /bin/false
     fi
  fi
}
aaa(){
cat <<END
###########################
#    1.start
#    2.stop
#    3.restart
#    4.exit
###########################
END
read -p "please input {1|2|3|4}" b
}
bbb(){
cat <<END
###########################
#    1.start
#    2.stop
#    3.restart
#    4.exit
###########################
END
read -p "please input {1|2|3|4}" c
}
case "$a" in
3306)
    aaa
;;
3307)
    bbb
;;
exit)
    exit
;;
esac
case "$b" in
1)
  mysql1_start
;;
2)
  mysql1_stop
;;
3)
  mysql1_stop
  sleep 3
  mysql1_start
;;
4)
  exit 2
;;
esac
case "$c" in
1)
  mysql2_start
;;
2)
  mysql2_stop
;;
3)
  mysql2_stop
  sleep 3
  mysql2_start
;;
4)
  exit 2
;;
esac

企业实战题8:

　　如何实现对MySQL数据库进行分库备份，请用脚本实现
　　本文由刘康同学提供

[root@db02 tmp]# cat MoreDatabasesBak.sh
#!/bin/bash
. /etc/init.d/functions
PORT='3306'
BAKUPDIR='/server/backup'
MYSQLUSER='root'
MYSQLPASS='oldboy'
SOCK="/data/${PORT}/mysql.sock"
CMDDIR="/application/mysql/bin"
MYSQL="${CMDDIR}/mysql -u${MYSQLUSER} -p${MYSQLPASS} -S${SOCK}"
DBNAME=`${MYSQL} -e "show databases;"|sed 1d|egrep -v "_schema|mysql"`
AYYAYDB=($DBNAME)
MYSQLDUMP="${CMDDIR}/mysqldump -u${MYSQLUSER} -p${MYSQLPASS} -S${SOCK}"
function BAKDB(){
    for((n=0;n<${#AYYAYDB[*]};n++))
           do
        ${MYSQLDUMP} --events -B ${AYYAYDB[$n]} |gzip >${BAKUPDIR}/${AYYAYDB[$n]}_$(date +%T-%F)_bak.sql.gz
        RETVAL=$?
        if [ $RETVAL -eq 0 ]
            then
                echo "${AYYAYDB[$n]} bak successfull `date +%F-%T` " >>/tmp/DBbakstatus.log
            else
                echo "${AYYAYDB[$n]} bak fail `date +%F-%T` " >>/tmp/DBbakstatus.log
        fi     
           done
    mail -s "DB STATUS" www.abcdocker.com@qq.com < /tmp/DBbakstatus.log
    return
}
function DBstatus(){
[ -d ${BAKUPDIR} ] || mkdir ${BAKUPDIR} -p
${MYSQL} -e "show full processlist;" &> /dev/null
RETVAL=$?
if [ $RETVAL -eq 0 ]
  then
        >/tmp/DBbakstatus.log
        BAKDB 
  else
       echo "DB BAD!!!  `date +%F-%T`" | mail -s "DB BAD!!!" www.abcdocker.com@qq.com
        exit
fi
}
DBstatus

企业实战题9:

　　如何实现对MySQL数据库进行分库加分表备份，请用脚本实现
本脚本还是由刘康同学提供

[root@db02 tmp]# cat MoreTablesBak.sh
#!/bin/bash
. /etc/init.d/functions
PORT='3306'
BAKUPDIR='/server/backup'
MYSQLUSER='root'
MYSQLPASS='oldboy'
SOCK="/data/${PORT}/mysql.sock"
CMDDIR="/application/mysql/bin"
MYSQL="${CMDDIR}/mysql -u${MYSQLUSER} -p${MYSQLPASS} -S${SOCK}"
DBNAME=`${MYSQL} -e "show databases;"|sed 1d|egrep -v "_schema|mysql"`
AYYAYDB=($DBNAME)
MYSQLDUMP="${CMDDIR}/mysqldump -u${MYSQLUSER} -p${MYSQLPASS} -S${SOCK}"
function BAKDB(){
DBNAME=`${MYSQL} -e "show databases;"|sed 1d|egrep -v "_schema|mysql"`
AYYAYDB=($DBNAME)
    for((n=0;n<${#AYYAYDB[*]};n++))
           do
    TABLE_BAK_DIR="${BAKUPDIR}/${AYYAYDB[$n]}"
    TABLENAME=`${MYSQL} -e "show tables from ${AYYAYDB[$n]};"|sed 1d`
    ARRAYTABLE=(${TABLENAME})
        for((i=0;i<${#ARRAYTABLE[*]};i++))
            do
        [ -d ${TABLE_BAK_DIR}  ] || mkdir ${TABLE_BAK_DIR} -p
        ${MYSQLDUMP} ${AYYAYDB[$n]} ${ARRAYTABLE[$i]} |gzip >${TABLE_BAK_DIR}/${ARRAYTABLE[$i]}_$(date +%T-%F)_bak.sql.gz
        RETVAL=$?
        if [ $RETVAL -eq 0 ]
            then
                echo "${AYYAYDB[$n]}_${ARRAYTABLE[$i]} bak successfull `date +%F-%T` " >>/tmp/DB_table_bakstatus.log
            else
                echo "${AYYAYDB[$n]}_${ARRAYTABLE[$i]} bak fail `date +%F-%T` " >>/tmp/DB_table_bakstatus.log
        fi 
        done 
           done
    mail -s "DB STATUS" www.abcdocker.com@qq.com < /tmp/DB_table_bakstatus.log
    return
}
function DBstatus(){
[ -d ${BAKUPDIR} ] || mkdir ${BAKUPDIR} -p
${MYSQL} -e "show full processlist;" &> /dev/null
RETVAL=$?
if [ $RETVAL -eq 0 ]
  then
        >/tmp/DB_table_bakstatus.log
        BAKDB 
  else
       echo "DB BAD!!!  `date +%F-%T`" | mail -s "DB BAD!!!" www.abcdocker.com@qq.com
        exit
fi
}
DBstatus

企业面试题10：

请用至少两种方法实现！
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.

没讲数组之前自己做的：
[root@web02 ~]# cat /server/scripts/28/bash.sh
#!/bin/bash
for n in `echo I am oldboy teacher welcome to oldboy training class.`
do
AAA=$( echo $n|wc -c)
if [ $AAA -gt 7 ];then
     continue;
fi
echo $n
done

第一种方法：不使用数组

[root@db02 scripts]# cat 3.sh
#!/bin/bash
for i in I am oldboy teacher welcome to oldboy training class.
do
   if [ "${#i}" -le 6 ]
     then
        echo $i
   fi
done

第二种方法：使用数组

[root@db02 scripts]# cat 3.sh
#!/bin/bash
array=(I am oldboy teacher welcome to oldboy training class.)
for ((i=0;i<${#array[@]};i++))
do
   if [ "`echo ${array[i]}|wc -L`" -le 6 ]
   then
       echo ${array[i]}
   fi
done

第三种方法：命令拼接

echo "I am oldboy teacher welcome to oldboy training class." | awk '{for(i=1;i<=NF;i++){a=length($i);if(a <= 6){print $i}}}'

企业面试题11：

　　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。

[root@db01 scripts]# cat read.sh
#!/bin/sh
#no.1
read -p "Pls input two num:" a b
[ -z "$a" -o -z "$b" ]&&{
   echo "must be two num."
   exit 1
}
#no.2
expr $a + 1 &>/dev/null
[ $? -ne 0 ]&&{
    echo "First arg must be int."
    exit 2
}
expr $b + 1 &>/dev/null
[ $? -ne 0 ]&&{
    echo "Second arg must be int."
    exit 3
}
#no.3
[ $a -gt $b ]&&{
  echo "$a > $b"
  exit 0
}
[ $a -eq $b ]&&{
  echo "$a = $b"
  exit 0
}
[ $a -lt $b ]&&{
  echo "$a < $b"
  exit 0
}

企业面试题12：

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。
由10组黑哥提供（吴依）
黑哥博客：www.dockerwy.com

#!/bin/bash
cat <<EOF
1.[install lamp]
2.[install lnmp]
3.[exit]
pls input the num you want:
EOF
read -p "please input number 1-3:" a
lamp() {
  if [ -f /server/scripts/lamp.sh ];then
echo "startinstalling lamp."
sleep 2
sh /server/scripts/lamp.sh
else
echo "file does not exist"
  fi
exit 0
}
lnmp () {
  if [ -f /server/scripts/lnmp.sh ];then
echo "startinstalling lnmp."
sleep 3
sh /server/scripts/lnmp.sh
else
echo "file does not exist"
  fi
exit 0
}
case $a in
  1)
lamp
;;
  2)
lnmp
;;
  3)
exit 0
;;
  *)
echo "pls input the num you want:"
;;
esac

企业面试题13：

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。
思路
1、监控的三种方式
　　通过进程名监控 ps -ef|grep name
　　通过端口监控 netstat -lntup|grep port/lsof -i:80
　　通过链接信息上的进程名 netstat -lntup|grep port
2、等待一分钟
3、后台执行 nohup

#!/bin/bash
[ -f /etc/init.d/functions ] && . /etc/init.d/functions
check_httpd(){
count=`ps -ef|grep nginx|grep -v grep|wc -l`
      if [ "$count" -ne 0 ]
      then
        action "nginx is ok" /bin/true
      else
        action "nginx is dead" /bin/false
      fi
    }
    check_httpd_port(){
      count=`netstat -lntup|grep 8080|wc -l`
      if [ "$count" -ne 0 ]
      then
        action "nginx is ok" /bin/true
      else
        action "nginx is dead" /bin/false
      fi
    }

企业面试题14：

　　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。
感谢乔飞翔同学的分享

[root@db02 scripts]# cat mem.sh
#!/bin/bash
########################
#date:2016-07-17       #
#author:fxqiao         #
#QQ:827724746          #
#E-mail:qfx1995@163.com#
########################
#echo -ne "\033[0;33m"
echo -ne "\E[1;32m"
cat<<EOT
                                  _oo0oo_
                                 088888880
                                 88" . "88
                                 (| -_- |)
                                  0\ = /0
                               ___/'---'\___
                             .' \\\\|     |// '.
                            / \\\\|||  :  |||// \\
                           /_ ||||| -:- |||||- \\
                          |   | \\\\\\  -  /// |   |
                          | \_|  ''\---/''  |_/ |
                          \  .-\__  '-'  __/-.  /
                        ___'. .'  /--.--\  '. .'___
                     ."" '<  '.___\_<|>_/___.' >'  "".
                    | | : '-  \'.;'\ _ /';.'/ - ' : | |
                    \  \ '_.   \_ __\ /__ _/   .-' /  /
                ====='-.____'.___ \_____/___.-'____.-'=====
                                  '=---='
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
                        佛祖保佑    iii    服务正常
EOT
echo -ne "\E[0m"
[ -f /etc/init.d/functions ] && . /etc/init.d/functions
###variables
RETVAL=0
###color
RED_COLOR='\E[1;31m'
GREEN_COLOR='\E[1;32m'
YELLOW_COLOR='\E[1;33m'
BLUE_COLOR='\E[1;34m'
RES='\E[0m'
####menu list
menu() {
cat <<EOF
############################
  1 memcached status
  2 memcached stop
  3 memcached get_hits
  4 quit
EOF
}
status() {
Set=$(printf "set key1 0 0 6\r\noldboy\r\n"|nc 127.0.0.1 11211|grep STORED|wc -l)
Get=$(printf "get key1\r\n"|nc 127.0.0.1 11211|grep oldboy|wc -l)
Port=$(netstat -lntup|grep memcached|wc -l)
  if [ $Port -ge 4 ];then
     Num=$(expr $Set + $Get)
     if [ $Num -eq 2 ];then
        action "Memcached server is running" /bin/true
     else
        action "Memcached server is not normal" /bin/false
     fi
  else
     action "Memcached server is not running" /bin/false
     read -t 10 -p "Memcached server whether open:[y/n]:" b
     if [ "$b" == "y" -o "$b" == "Y" ];then
        /usr/bin/memcached -m 16m -p 11211 -d -u root -c 8192
        action "Memcached server is starting" /bin/true
     elif [ "$b" == "n" -o "$b" == "N" ];then
        echo -e "$YELLOW_COLOR Goodbye.............$RES"
     fi
  fi
  return $RETVAL
}
stop() {
Port=$(netstat -lntup|grep memcached|wc -l)
  if [ $Port -ge 4 ];then
     pkill memcached &>/dev/null
     RETVAL=$?
     if [ $RETVAL -eq 0 ];then
        action "Memcached server is stopping" /bin/true
     else
        action "Memcached server is stopping" /bin/false
     fi
  else
     action "Memcached server not running" /bin/false
  fi
}
get_hits() {
Cmd_get=$(printf "stats\r\n"|nc 127.0.0.1 11211|grep "cmd_get"|awk '{print $3}')
Get_hits=$(printf "stats\r\n"|nc 127.0.0.1 11211|grep "get_hits"|awk '{print $3}')
Get_misses=$(printf "stats\r\n"|nc 127.0.0.1 11211|grep "get_misses"|awk '{print $3}')
Port=$(netstat -lntup|grep memcached|wc -l)
  if [ $Port -ge 4 ];then
     echo "A total of cmd_get is $Cmd_get"
     sleep 1
     echo "A total of get_hits is $Get_hits"
     sleep 1
     echo "A total of get_misses is $Get_misses"
  else
     action "Memcached is not running" /bin/false
  fi
  return $RETVAL
}
main() {
while true
do
menu
read -t 10 -p "Please input number:" a
expr $a + 1 &>/dev/null
if [ $? -ne 0 ];then
   echo -e "$BLUE_COLOR Please input error,not int $RES"
   exit 1
fi
case "$a" in
  1)
    status
    RETVAL=$?
    ;;
  2)
    stop
    RETVAL=$?
    ;;
  3)
    get_hits
    RETVAL=$?
    ;;
  4)
    clear
        echo "##############################################"
    echo -e "$GREEN_COLOR `figlet GoodBye` $RES"
    echo "##############################################"
    exit 0
    ;;
  *)
    echo -e "$RED_COLOR input error $RES"
esac
done
}
main
exit $RETVAL

企业面试题15：

面试及实战考试题：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)。

[root@db02 tmp]# cat html.sh
#!/bin/sh
html_dir=/var/html/www
html_file=`find /var/html/www -type f`
check_dir=/tmp/checkdir
[ ! -d $check_dir ] && mkdir $check_dir
for n in $html_file
do
  md5sum $n >>$check_dir/1.txt
done
while true
do
  md5sum -c $check_dir/1.txt|grep FAILED >>$check_dir/2.txt
  [ -s $check_dir/2.txt ] && \
  echo "`cat $check_dir/2.txt`"|mail -s "date:`date +%F-%H:%M:%S` Web is dangerous" 18576749166@163.com
  >$check_dir/2.txt
sleep 3
done

企业面试题16：

企业案例: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。

[root@www tmp]# cat 123.sh
#!/bin/bash
##################
#I am yuhongcong
#qq:604419314
#################
# Comments to support chkconfig on RedHat Linux
# chkconfig: 2345 64 36
status1=$(ps -ef | egrep "rsync --daemon.*rsyncd.conf" | grep -v 'grep')
pidfile="/etc/rsync/rsyncd.pid"
start_rsync="rsync --daemon --config=/etc/rsync/rsyncd.conf"
function rsyncstart() {
    if [ "${status1}X" == "X" ];then
        rm -f $pidfile      
        ${start_rsync}  
        status2=$(ps -ef | egrep "rsync --daemon.*rsyncd.conf" | grep -v 'grep') 
        if [  "${status2}X" != "X"  ];then
            echo "rsync service start.......OK"
        fi
    else
        echo "rsync service is running !"   
    fi
}
function rsyncstop() {
    if [ "${status1}X" != "X" ];then
        kill -9 $(cat $pidfile)
        status2=$(ps -ef | egrep "rsync --daemon.*rsyncd.conf" | grep -v 'grep') 
        if [ "${statusw2}X" == "X" ];then
            echo "rsync service stop.......OK"
        fi
    else
        echo "rsync service is not running !"   
    fi
}
function rsyncstatus() {
    if [ "${status1}X" != "X" ];then
        echo "rsync service is running !"  
    else
         echo "rsync service is not running !" 
    fi
}
function rsyncrestart() {
    if [ "${status1}X" == "X" ];then
               echo "rsync service is not running..."
               rsyncstart
        else
               rsyncstop
               rsyncstart   
        fi      
} 
case $1 in
        "start")
               rsyncstart
                ;;
        "stop")
               rsyncstop
                ;;
        "status")
               rsyncstatus
               ;;
        "restart")
               rsyncrestart
               ;;
        *)
          echo
                echo  "Usage: $0 start|stop|restart|status"
          echo
esac

企业面试题17：

老男孩教育天津项目学生实践抓阄题目：
　　好消息，老男孩培训学生外出企业项目实践机会（第6次）来了（本月中旬），但是，名额有限，队员限3人（班长带队）。
因此需要挑选学生，因此需要一个抓阄的程序：
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，程序不能退出继续等待别的学生输入。

[root@db02 tmp]# cat select17.sh
#!/bin/sh
> /tmp/temp.txt
input(){
while true
do
  read -p "pls input your name:" name
  if [ -z $name ]
  then
    continue
  elif [ $name == "0" ]
  then
    break
  fi
  rand=$((RANDOM%100))
  echo -e $rand"\t"$name >>/tmp/temp.txt
done
}
output(){
cat /tmp/temp.txt |sort -n -k1 -r|sed '3a#################'
}
main(){
input
output
}
main

企业面试题18：

　　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
890684b

方法一：

#!/bin/bash
. /etc/init.d/functions
MD5PASS=(
21029299
00205d1c
a3da1677
1f6d12dd
890684b
)
for ((n=0;n<=32767;n++))
do
for((i=0;i<${#MD5PASS[*]};i++))
do
        md5=`echo $n | md5sum|cut -c 1-8`
        if [ "$md5" == ${MD5PASS[$i]} ]
                then
                echo "$n" "${MD5PASS[$i]} "
                fi
done
done

方法二：

[root@openvpn-server ~]# cat md5sum.sh
#!/bin/sh
a=(
21029299
00205d1c
a3da1677
1f6d12dd
890684b
)
for i in `seq 32767`
do
   source=`echo $i|md5sum|cut -c 1-8`
   for j in ${a[@]}
   do
   if [ $source == $j ];then
      echo $source "-->" $i
   fi
   done
done

方法三：

[root@m01 ~]# cat mianshiti6.sh
#!/bin/bash
mima=(
21029299
00205d1c
a3da1677
1f6d12dd
890684b
)
for i in {1..32767}
do
  num=`echo $i | md5sum | cut -c -8`
  for n in ${mima[*]}
   do
    if [ "$num" == "$n"  ]
     then
      echo "$i match $n"
      continue
    fi
  done
done

企业面试题19：

批量检查多个网站地址是否正常
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

[root@db02 scripts]# cat aaa.sh
#!/bin/sh
################
#Author:YuHongCong
#604419314@qq.com
################
[ -f /etc/init.d/functions ] && . /etc/init.d/functions
URLS=(
http://www.etiantian.org
http://www.taobao.com
http://oldboy.blog.51cto.com
http://10.0.0.70
)
CHECK_URL(){
  wget -T 3 --spider --tries=2 $1 &>/dev/null
  if [ $? -eq 0 ]
  then
    return 0
  else
    return 1
  fi
}
MON_URL(){
for url in ${URLS[*]}
do
  CHECK_URL $url
  if [ $? -eq 0 ]
  then
    action "$url" /bin/true
  else
    action "$url" /bin/false
  fi
done
}
main(){
while true
do
  MON_URL
  sleep 10
done
}
main

1.png-178kB
老男孩推荐：（包含倒计时的方法）

[root@db01 shizhan]# cat oldboy01.sh  
#!/bin/sh
################
#Author:oldboy
#31333741@qq.com
################
[ -f /etc/init.d/functions ] && . /etc/init.d/functions
URLS=(
http://www.etiantian.org
http://www.taobao.com
http://oldboy.blog.51cto.com
http://10.0.0.70
)
LTIME(){
echo -n "time;"
for n in {1..10}
do
  if [ $n -eq 10 ]
   then
    echo "start"
  else
    echo -n .
  fi
  sleep 1
done
}
CHECK_URL(){
  wget -T 3 --spider --tries=2 $1 &>/dev/null
  if [ $? -eq 0 ]
  then
    return 0
  else
    return 1
  fi
}
MON_URL(){
for url in ${URLS[*]}
do
  CHECK_URL $url
  if [ $? -eq 0 ]
  then
    action "$url" /bin/true
  else
    action "$url" /bin/false
  fi
done
}
main(){
while true
do
  LTIME
  MON_URL
  sleep 10
done
}
main

企业面试题20(中企动力)：

用shell处理以下内容
1、按单词出现频率降序排序！
2、按字母出现频率降序排序！

the squid project provides a number of resources toassist users design,implement and support squid installations. Please browsethe documentation and support sections for more infomation

#!/bin/sh
str="the squid project provides a number of resources toassist users design,implement and support squid installations. Please browsethe documentation and support sections for more infomation"
words(){
echo $str|sed 's#[^a-zA-Z]# #g'|tr " " "\n"|grep -v "^$"|sort|uniq -c|sort -r -n
}
letters(){
echo $str|grep -o "."|sort|egrep -v " |^$|[^a-zA-Z]"|uniq -c|sort -n -r
}
case $1 in
words)
  words
  ;;
letters)
  letters
  ;;
*)
  echo "usage:$0 {words|letters}"
esac

企业面试题22:

　　开发通过web界面展示监控Nginx代理节点状态，效果图如下。
2.png-376.9kB
文件打包密码：xso0
脚本及内容请下载
3.png-7.9kB

lvs+keepalived集群部分Shell企业案例：

企业面试题23、

【LVS主节点】手工开发ipvsadm管理lvs的脚本ip_vs

实现：/etc/init.d/lvs {start|stop|restart}

[root@www tmp]# cat lvs.sh 
#!/bin/bash
if [ $UID -ne 0 ];then
  echo "Permission denied (you must be root)"
  exit 1
fi
[ -f /etc/init.d/functions ] && . /etc/init.d/functions
vip_netmask=10.0.0.3/24
vip=10.0.0.3
service_addr=10.0.0.3:80
rs=(
10.0.0.7:80
10.0.0.8:80
)
start() {
    #add vip
    ifconfig|grep $vip &>/dev/null
    if [ $? -ne 0 ];then
      ip addr add $vip_netmask dev eth0 label eth0:0 && \
      action "add vip $vip_netmask" /bin/true
    else
      echo "vip $vip_netmask already exists."
    fi
    lvs_table=$(ipvsadm -ln|grep "$vip"|wc -l) 
    if [ $lvs_table -eq 1 ];then
      echo "virtual server already exists."
    else
      #add virtual server
      ipvsadm -A -t $service_addr -s wrr && \
      action "add virtual server $service_addr" /bin/true
    fi
    for ip in ${rs[@]};do
      rs_num=$(ipvsadm -ln|grep "$ip"|wc -l)
      if [ $rs_num -eq 1 ];then
        echo "real server $ip already exists."
      else
        #add real server
        ipvsadm -a -t $service_addr -r $ip -g -w 1 && \
        action "add real server $ip" /bin/true
      fi
    done
    #set tcp tcpfin udp connection timeout
    ipvsadm --set 30 5 60 && \
    action "set tcp tcpfin udp connection timeout values." /bin/true
}
stop() {
    ifconfig|grep $vip &>/dev/null
    if [ $? -ne 0 ];then
      echo "without vip $vip"
    else
      #delete vip 
      ip addr del $vip_netmask dev eth0 label eth0:0 && \
      action "delete vip $vip_netmask." /bin/true
    fi
    lvs_table=$(ipvsadm -ln|grep "$vip"|wc -l)
    for ip in ${rs[@]};do
      rs_num=$(ipvsadm -ln|grep "$ip"|wc -l)
      let lvs_table+=rs_num
    done
    if [ $lvs_table -ge 1 ];then
      #clear all table
      ipvsadm -C && \
      action "clear all lvs table." /bin/true
    else
      echo "lvs table is empty."
    fi
}
case "$1" in
    start)
    start
    ;;
    stop)
    stop
    ;;
    restart)
    stop
    sleep 2
    start
    ;;
    *)
    echo "USAGE: $0 {start|stop|restart}"
esac

企业面试题24

　　【LVS主节点】模拟keepalived健康检查功能管理LVS节点，
当节点挂掉（检测2次，间隔2秒）从服务器池中剔除，好了（检测2次，间隔2秒）加进来
提示：利用ipvsadm命令实现添加和减少LVS节点。

[root@www tmp]# cat lvs_check_rs.sh
#!/bin/bash
vip=10.0.0.3
rs_ip=(
10.0.0.8
10.0.0.7
)
remove_check() {
  for rs in ${rs_ip[@]};do
    ipvsadm -ln|grep $rs &>/dev/null
    if [ $? -eq 0 ];then
        rs_donw=0
        a_group_down=0
      for i in 1 2;do
        rs_down=$(nmap -p 80 $rs|grep open|wc -l)
        let a_group_down+=rs_down
        sleep 2
      done
      if [ $a_group_down -eq 0 ];then
        ipvsadm -d -t ${vip}:80 -r ${rs}:80
      fi
    fi
  done
}
join_check() {
  for rs in ${rs_ip[@]};do
    ipvsadm -ln|grep $rs &>/dev/null
    if [ $? -ne 0 ];then
      a_group_up=0
      rs_up=0
      for j in 1 2;do
        rs_up=$(nmap -p 80 $rs|grep open|wc -l)
        let a_group_up+=rs_up
        sleep 2
      done
      if [ $a_group_up -eq 2 ];then
        ipvsadm -a -t ${vip}:80 -r ${rs}:80 -g -w 1
      fi
    fi
  done
}
check_rs() {
  while true;do
  remove_check
  sleep 1
  join_check
  sleep 1
  done
}
check_rs

企业面试题25

【LVS客户端节点】开发LVS客户端设置VIP以及抑制ARP的管理脚本
实现：/etc/init.d/lvsclient {start|stop|restart}

 [root@web01-lnmp-09 scripts]# cat /etc/init.d/lvsclient
#!/bin/bash
#chkconfig: 2345 37 57
#Write by Bevin 2016
#LVS_Nginx
export PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin
[ -f /etc/init.d/functions ] && source /etc/init.d/functions
#Step 1
function L_ipadd() {
  VIPRES=`ip addr|grep 10.0.0.12|wc -l`
  if [ $VIPRES -eq 0 ]
    then
      ip addr add 10.0.0.12/32 dev lo label lo:12
      route add -host 10.0.0.12 dev lo
      sleep 1
      VIPRES=`ip addr|grep 10.0.0.12|wc -l`
      if [ $VIPRES -eq 0 ]
        then
          ip addr add 10.0.0.12/32 dev lo label lo:12
          route add -host 10.0.0.12 dev lo
          sleep 1
          VIPRES=`ip addr|grep 10.0.0.12|wc -l`
          if [ $VIPRES -eq 0 ]
            then
              action "ip addr add 10.0.0.12/32 ..."   /bin/false
              exit 1
            else
              action "ip addr add 10.0.0.12/32 ..."   /bin/true
          fi
        else
          action "ip addr add 10.0.0.12/32 ..."   /bin/true
      fi
    else
      action "ip addr add 10.0.0.12/32 is exist."
  fi
  echo "1" > /proc/sys/net/ipv4/conf/lo/arp_ignore
  echo "2" > /proc/sys/net/ipv4/conf/lo/arp_announce
  echo "1" > /proc/sys/net/ipv4/conf/all/arp_ignore
  echo "2" > /proc/sys/net/ipv4/conf/all/arp_announce
}
function L_ipdel() {
  VIPRES=`ip addr|grep 10.0.0.12|wc -l`
  if [ $VIPRES -ne 0 ]
    then
      ip addr del 10.0.0.12/32 dev lo
      route del -host 10.0.0.12 dev lo
      sleep 1
      VIPRES=`ip addr|grep 10.0.0.12|wc -l`
      if [ $VIPRES -ne 0 ]
        then
          action "ip addr del 10.0.0.12/32 ..."  /bin/false
          exit 1
        else
          action "ip addr del 10.0.0.12/32 ..."  /bin/true
      fi
    else
          action "ip addr del 10.0.0.12/32 ..."   /bin/true
  fi
  echo "0" > /proc/sys/net/ipv4/conf/lo/arp_ignore
  echo "0" > /proc/sys/net/ipv4/conf/lo/arp_announce
  echo "0" > /proc/sys/net/ipv4/conf/all/arp_ignore
  echo "0" > /proc/sys/net/ipv4/conf/all/arp_announce
}
#Step 2
function L_exec() {
  case "$1" in
    start)
      L_ipadd
    ;;
    stop)
      L_ipdel
    ;;
    status)
      VIPRES=`ip addr|grep 10.0.0.12|wc -l`
      sleep 1
      if [ $VIPRES -ne 0 ]
        then
          echo "LVS Nginx is working"
        else
          echo "LVS Nginx is not working"
      fi
    ;;
    restart)
      VIPRES=`ip addr|grep 10.0.0.12|wc -l`
      if [ $VIPRES -ne 0 ]
        then
          L_ipdel
          sleep 1
          L_ipadd
        else
          echo  "ip 10.0.0.12 is not working"
          sleep 1
          L_ipadd
      fi
    ;;
    *)
      echo "USAGE: $0 {start|stop|restart|status}"
  esac
}

企业面试题26

【LVS备节点】模拟keepalved vrrp功能，监听主节点，如果主节点不可访问则备节点启动并配置LVS实现接管主节点的资源提供服务（提醒：注意ARP缓存）

[root@lvs-lb01-05 scripts]# cat lvs.sh
#!/bin/bash
#Write by Bevin 2016
export PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin
[ -f /etc/init.d/functions ] && source /etc/init.d/functions
#Step 1 Instal ip_vs
Ch_ipvs=`rpm -qa ipvsadm|wc -l`
if [ $Ch_ipvs -eq 0 ]
  then
    yum install ipvsadm -y
fi
#Step 2 Functions
VIP=10.0.0.12
V_TAIL=12
RIP=(
9
10
)
function L_LVS_VIP_RIP() {
  VIPRES=`ip addr|grep $VIP|wc -l`
  if [ $VIPRES -eq 0 ]
    then
      ip addr add $VIP/24 dev eth0 label eth0:$V_TAIL
      ipvsadm -C
      ipvsadm -A -t $VIP:80 -s rr
      for n in ${RIP[*]}
      do
        ipvsadm -a -t $VIP:80 -r 10.0.0.$n:80 -g
      done
    else
      ipvsadm -C
      ipvsadm -A -t $VIP:80 -s rr
      for n in ${RIP[*]}
      do
        ipvsadm -a -t $VIP:80 -r 10.0.0.$n:80 -g
      done
  fi
}
function L_check_vip() {
  VIPRES=`ip addr|grep $VIP|wc -l`
  if [ $VIPRES -eq 0 ]
    then
      L_LVS_VIP_RIP
      sleep 5
      if [ $VIPRES -eq 0 ]
        then
          L_LVS_VIP_RIP
          sleep 5
          if [ $VIPRES -eq 0 ]
            then
              echo "Warning: lb01: $VIP is down."|mail -s txbevin@sina.com
              exit 1
          fi
      fi
  fi
  sleep 5
}
function L_check_rip() {
  for n in ${RIP[*]}
  do
    CurlRes=`curl -I -s 10.0.0.$n|grep -E "200|301|302"|wc -l`
    if [ $CurlRes -ne 0 ]
      then
        RS=`ipvsadm -Ln|grep 10.0.0.$n|wc -l`
        if [ $RS -eq 0 ]
          then
            ipvsadm -a -t $VIP:80 -r 10.0.0.$n:80
        fi
      else
        ipvsadm -d -t $VIP:80 -r 10.0.0.$n:80
        mail -s "10.0.0.$n nginx is down at $(date +%F-%T)." txbevin@sina.com
        continue
    fi
  done
  sleep 5
}
#Step 3
L_LVS_VIP_RIP
while true
do
  L_check_vip
  sleep 1
  L_check_rip
  sleep 1
done

后面几道题如果大家会可以把答案发送给我
　　　　　mail:new_oldboy@163.com
－－－－－－－－－－－－－－－－－－－

企业面试题27

　　请用shell或Python编写一个正方形(oldboy_square.sh)，接收用户输入的数字。
例如：

[root@oldboy ~]# sh oldboy_square1.sh
Please Enter a number:5
++++++++++
++++++++++
++++++++++
++++++++++
++++++++++
[root@oldboy ~]# sh oldboy_square2.sh 
Please Enter a number:9
■■■■■■■■■
■■■■■■■■■
■■■■■■■■■
■■■■■■■■■
■■■■■■■■■
■■■■■■■■■
■■■■■■■■■
■■■■■■■■■
■■■■■■■■■

企业面试题28

　　请用shell或Python编写一个等腰三角形(oldboy2_triangle.sh)，接收用户输入的数字。
例如：

[root@oldboy ~]# sh oldboy2_triangle.sh
Please Enter a number:5
    *
   ***
  *****
*******
*********
[root@oldboy ~]# sh oldboy2_triangle.sh
Please Enter a number:8
       *
      ***
     *****
    *******
   *********
  ***********
*************
***************

企业面试题29

　　请用shell或Python编写一个画直角梯形程序(oldboy4.sh)，接收用户输入的参数n，m
例如：

[root@oldboy ~]# sh oldboy4.sh 4 6
****
*****
******

27,28,29三道题可以参考
http://oldboy.blog.51cto.com/2561410/1718607

本文出自 “老男孩linux培训”
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