1.使用for循环在/touch目录下通过随机小写10个字母加固定字符串test批量创建10个html文件，

-rw-r--r-- 1 root root  477 Jul 20 13:59 touch.sh
[root@sf106232 mianshi1]# cat touch.sh 
#!/bin/bash
#*****************************************************
#         Author: suixiaofeng
#           blog:https://bk.devopstack.cn
#          Email: 258818040@qq.com 
#  Last modified: 2017-07-20 13:55
#       Filename: touch.sh
#    Description: 
#****************************************************
path=./touch
[ -d "$path" ] || mkdir $path
for((i=0;i<10;i++))
do 

 random=`echo $RANDOM|md5sum|sed 's#[^a-z]##g'|cut -c 1-10`
 touch $path/${random}_test.html
done 

2.批量改名。

gtj_1223.html
rename  gtj ggg gtj_1223.html 
[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 

3.　写一个脚本解决DOS攻击生产案例

#!/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 $*

4.1、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。

#!/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

5.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

6.手工开发ipvsadm管理lvs的脚本ip_vs

#!/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

7.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}

#!/bin/bash
#chkconfig: 2345 37 57
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
}

8.公司网络地址的划分

9.本例通过计算主机数来划分子网。

AD：让我们在it的道路上越行越远!