作业--SHELL脚本编程练习答案（多版本）

练习：
1、编写脚本 systeminfo.sh，显示当前主机系统信息，包括:主机名，IPv4地址，操作系统版本，内核
版本，CPU型号，内存大小，硬盘大小

#!/bin/bash
YELLOW='\e[1;33m'
RED='\e[1;31m'
END='\e[0m'

echo -e "${YELLOW}++++++++++++++++++++++++++++++++++++++++++${END}"
echo -e "${RED}HOSTNAME:        `hostname`${END}"
echo -e "${RED}IPADDR:          `hostname -I`${END}"
echo -e "${RED}OS's version:    `cat /etc/centos-release`${END}"
echo -e "${RED}Kernel version:  `uname -r`${END}"
echo -e "${RED}CPU:            `lscpu |egrep '^Model name'|tr -s ' '|cut -d: -f2`${END}"
echo -e "${RED}Memory size:     `free -h|sed -rn '2p'|tr -s ' '|cut -d' ' -f2`${END}"
echo -e "${RED}Disk size:       `lsblk |sed -n '2p'|egrep -o '([0-9]+)G'`${END}"
echo -e "${YELLOW}++++++++++++++++++++++++++++++++++++++++++${END}"

2、编写脚本 backup.sh，可实现每日将 /etc/ 目录备份到 /backup/etcYYYY-mm-dd中
版本1：

#!/bin/bash
RED='\e[1;31m'
GREEN='\e[1;32m'
END='\e[0m'
SOURCE="/etc"
DEST="/backup"

[ ! -d $DEST ] && { mkdir $DEST;echo -e "${RED}Start backup...${END}";sleep 3;cp -av $SOURCE $DEST/etc`date +%F`;echo -e "${GREEN}Back is finished.${END}"; } || { echo -e "${RED}Start backup...${END}";sleep 3;cp -av $SOURCE $DEST/etc`date +%F`;echo -e "${GREEN}Back is finished.${END}"; }

版本2：

#!/bin/bash
RED='\e[1;31m'
GREEN='\e[1;32m'
END='\e[0m'
SOURCE="/etc"
DEST="/backup"

if [ ! -d $DEST ];then
mkdir $DEST
echo -e "${RED}Start backup...${END}"
sleep 3
cp -av $SOURCE $DEST/etc`date +%F`
echo -e "${GREEN}Back is finished.${END}"
else
echo -e "${RED}Start backup...${END}"
sleep 3
cp -av $SOURCE $DEST/etc`date +%F`
echo -e "${GREEN}Back is finished.${END}"
fi

3、编写脚本 disk.sh，显示当前硬盘分区中空间利用率最大的值

#!/bin/bash
COLOR='\e[1;36m'
END='\e[0m'
MAX=`df|egrep '^/dev/sd'|egrep -o '([0-9]+)%' |tr -d '%'|sort -nr|head -1`

echo -e "${COLOR}The maximum value of space is $MAX in the hard disk partition.${END}"

4、编写脚本 links.sh，显示正连接本主机的每个远程主机的IPv4地址和连接数，并按连接数从大到小排
序

#!/bin/bash
COLOR='\e[1;34m'
END='\e[0m'
RESULT=`netstat -tan|egrep 'ESTABLISHED'|tr -s ' ' :|cut -d: -f6|sort|uniq -c|sort -nr`

echo -e "${COLOR}Active Internet connections's status:\n${RESULT}${END}"

1、编写脚本 argsnum.sh，接受一个文件路径作为参数；如果参数个数小于1，则提示用户“至少应该给
一个参数”，并立即退出；如果参数个数不小于1，则显示第一个参数所指向的文件中的空白行数
版本1：

#!/bin/bash
[ $# -lt 1 ] && { echo -e "\e[1;31mPlease at least give an argument.\e[0m";exit 2; }
[ $# -ge 1 ] && echo -e "\e[1;35mBlank lines is `grep '^$' $1 $2 $3|wc -l`.\e[0m"

版本2：

#!/bin/bash
if [ $# -lt 1 ];then
echo -e "\e[1;31mPlease at least input a filename as an argument.\e[0m"
exit 2
else
echo -e "\e[1;36mBlank line is `egrep '^$' $1 $2 $3 | wc -l`.\e[0m"
fi

2、编写脚本 hostping.sh，接受一个主机的IPv4地址做为参数，测试是否可连通。如果能ping通，则提
示用户“该IP地址可访问”；如果不可ping通，则提示用户“该IP地址不可访问”
版本1：

#!/bin/bash
IP=10.0.0.7
RED='\e[1;31m'
GREEN='\e[1;32m'
ping -c1 -W1 $IP &> /dev/null && echo -e "${GREEN}${IP} is up.${END}" || echo -e "${RED}${IP} is down.${END}"

版本2：

#!/bin/bash
RED='\e[1;31m'
GREEN='\e[1;32m'
END='\e[0m'
IP=10.0.0.2
if ping -c1 -W1 $IP &> /dev/null;then
echo -e "${GREEN}${IP} is up.${END}"
else
echo -e "${RED}${IP} is down.${END}"
fi

版本3：

#!/bin/bash
IP=10.0.0
RED='\e[1;31m'
GREEN='\e[1;32m'
END='\e[0m'

for i in `seq 254`;do
ping -c1 -W1 ${IP}.${i} &> /dev/null && echo -e "${GREEN}${IP}.${i} is up.${END}" || echo -e "${RED}${IP}.${i} is down.${END}"
done

3、编写脚本 checkdisk.sh，检查磁盘分区空间和inode使用率，如果超过80%，就发广播警告空间将
满
版本1：

#!/bin/bash
WARN=20
GREEN='\e[1;32m'
END='\e[0m'
SPACE_USED=`df|egrep '^/dev/sd'|egrep -o '([0-9]+)%' |tr -d '%'|sort -nr|head -1`
INODE_USED=`df -i|egrep '^/dev/sd'|egrep -o '([0-9]+)%' |tr -d '%'|sort -nr|head -1`

[ $SPACE_USED -ge $WARN -o $INODE_USED -ge $WARN ] && echo "space will be full." | mail -s diskwarning 123456789@qq.com || echo -e "${GREEN}Disk space is enough.${END}"

版本2：

#!/bin/bash
WARN=20
YELLOW='\e[1;33m'
END='\e[0m'
DISK_USED=`df|egrep '/dev/sd'|egrep -o '([0-9]+)%'|tr -d '%'|sort -nr|head -1`
INODE_USED=`df -i|egrep '^/dev/sd'|egrep -o '([0-9]+)%' |tr -d '%'|sort -nr|head -1`

if [ $DISK_USED -ge $WARN -o $INODE_USED -ge $WARN ];then
echo "Disk space will be full." |mail -s Diskwarning 123456789@qq.com
else
echo -e "${YELLOW}Disk space is enough.${END}"
fi

版本3：

#!/bin/bash
WARN=10
RED='\e[1;31m'
BLUE='\e[1;34m'
END='\e[0m'

DISK_USED=`df|egrep '^/dev/sd'|egrep -o '([0-9]+)%' |tr -d '%'`

for i in $DISK_USED;do
[ $i -ge $WARN ] && echo -e "${RED}Disk space will be full.${END}" || echo -e "${BLUE}Disk space is enough.${END}"
done

4、编写脚本 per.sh，判断当前用户对指定参数文件，是否不可读并且不可写
版本1：

#!/bin/bash
read -p "Please input a filename: " FILE
[ ! -r $FILE -a ! -w $FILE ] && echo "$FILE is not readable and not writeable" || echo "$FILE is readable or writeable."

版本2：

#!/bin/bash
COLOR1='\e[1;33m'
COLOR2='\e[1;34m'
END='\e[0m'
if [ $# -ne 0 ];then
[ ! -r $1 -a ! -w $1 ] && echo -e "${COLOR1}$1 is not readable and not writeable.${END}" || echo -e "${COLOR2}$1 is readable or writeable.${END}"
else
echo -e "${COLOR1}Please input a file.${END}"
fi

5、编写脚本 excute.sh ，判断参数文件是否为sh后缀的普通文件，如果是，添加所有人可执行权限，
否则提示用户非脚本文件
版本1：

#!/bin/bash
RED='\e[1;31m'
YELLOW='\e[1;33m'
END='\e[0m'
read -p "Please input a filename: " FILE
[[ "$FILE" =~ ^.*\.sh$ ]] && { chmod a+x $FILE;echo -e "${YELLOW}${FILE}'s executeable is added.${END}"; }  || echo -e "${RED}${FILE} is not a script file.${END}"

版本2：

#!/bin/bash
RED='\e[1;31m'
YELLOW='\e[1;33m'
END='\e[0m'
read -p "Please input a filename: " FILE
if [[ "$FILE" =~ ^.*\.sh$ ]];then
chmod a+x $FILE
echo -e "${YELLOW}${FILE}'s executeable permission is added.${END}"
else
echo -e "${RED}${FILE} is not a script file.${END}"
fi

6、编写脚本 nologin.sh和 login.sh，实现禁止和允许普通用户登录系统
版本1：

#!/bin/bash
YELLOW='\e[1;33m'
END='\e[0m'
FILE="/etc/nologin"

[ ! -e $FILE ] && { touch $FILE; echo -e "${YELLOW}Prohibit common user login.${END}"; } || echo -e "${YELLOW}Cmmon user can not login.${END}"

版本2：

#!/bin/bash
YELLOW='\e[1;33m'
RED='\e[1;31m'
END='\e[0m'
FILE="/etc/nologin"

if [ ! -e $FILE ];then
touch $FILE
echo -e "${YELLOW}Prohibit common user login.${END}"
else
echo -e "${RED}Cmmon user can not login.${END}"
fi

练习
1、让所有用户的PATH环境变量的值多出一个路径，例如：/usr/local/apache/bin

echo "export PATH=/usr/local/apache/bin:$PATH" >> /etc/profile
source /etc/profile
echo $PATH

2、用户 root 登录时，将命令指示符变成红色，并自动启用如下别名： rm=‘rm -i’
cdnet=‘cd /etc/sysconfig/network-scripts/’
editnet=‘vim /etc/sysconfig/network-scripts/ifcfg-eth0’
editnet=‘vim /etc/sysconfig/network-scripts/ifcfg-eno16777736 或 ifcfg-ens33 ’ (如果系统是
CentOS7)

echo PS1="\[\e[1;32m\][\[\e[0m\]\[\e[1;32m\]\u\[\e[32m\]@\h\[\e[1;32m\] \W\[\e[1;32m\]]\[\e[0m\]\\$ " >> /etc/profile.d/env.sh
cat <<EOF >> ~/.bashrc
>rm='rm -i'
>cdnet='cd /etc/sysconfig/network-scripts/'
>editnet='vim /etc/sysconfig/network-scripts/ifcfg-eth0'
>EOF

3、任意用户登录系统时，显示红色字体的警示提醒信息“Hi,dangerous！”

echo -e "\e[1;31mHi,dangerous!\e[0m" >> /etc/motd

4、编写生成脚本基本格式的脚本，包括作者，联系方式，版本，时间，描述等

vim ~/.vimrc
set ts=2
set expandtab
set ignorecase
set autoindent
autocmd BufNewFile *.sh exec ":.call SetTitle()"
func SetTitle()
if expand("%:e") == 'sh'
call setline(1,"#!/bin/bash")
call setline(2,"#***********************************************")
call setline(3,"#Author:         Kingdom_xu")
call setline(4,"#Mail:           123456789@qq.com")
call setline(5,"#Version:        1.0")
call setline(6,"#Date:           ".strftime("%Y-%m-%d"))
call setline(7,"#FileName:       ".expand("%"))
call setline(8,"#Description:    The test script")
call setline(9,"#Copyright (C):  ".strftime("%Y")." All rights reserved")
call setline(10,"#***********************************************")
call setline(11,"")
endif
endfunc
autocmd BufNewFile * normal G

练习
1、编写脚本 createuser.sh，实现如下功能：使用一个用户名做为参数，如果指定参数的用户存在，就
显示其存在，否则添加之。并设置初始密码为123456，显示添加的用户的id号等信息，在此新用户第一
次登录时，会提示用户立即改密码，如果没有参数，就提示：请输入用户名
版本1：

#!/bin/bash
read -p "Please input a username: " NAME

[ -z $NAME ] && { echo -e "\e[1;33mPlease give a username.\e[0m";exit 2; }
id $NAME &> /dev/null && { echo -e "\e[1;36m$NAME is exist.\e[0m"; } || { useradd $NAME;echo $NAME:123456 | chpasswd $NAME;getent passwd $NAME;passwd -e $NAME &> /dev/null; }

版本2：

#!/bin/bash
read -p "Please input a username: " NAME

if [ -z $NAME ];then
echo -e "\e[1;37mInput a username.\e[0m"
exit 2
fi

if getent passwd $NAME;then
echo -e "\e[1;32m$NAME is exist.\e[0m"
else
useradd $NAME
echo $NAME:123456 | chpasswd $NAME
id $NAME
passwd -e $NAME &> /dev/null
fi

2、编写脚本 yesorno.sh，提示用户输入yes或no,并判断用户输入的是yes还是no,或是其它信息

#!/bin/bash
read -p "Please input yes or no: " ANS

case $ANS in
[Yy]|[Yy][Ee][Ss])
echo -e "\e[1;34mYour answer is YES.\e[0m"
;;
[Nn]|[Nn][Oo])
echo -e "\e[1;35mYour answer is NO.\e[0m"
;;
*)
echo -e "\e[1;33mPlease input yse or no.\e[0m"
esac

3、编写脚本 filetype.sh，判断用户输入文件路径，显示其文件类型（普通，目录，链接，其它文件类
型）

#!/bin/bash
read -p "Input a filename: " FILE
TYPE=`ls -ld $FILE|egrep -o '^.'`

case $TYPE in
-)
echo -e "\e[1;31m$FILE is a normal file.\e[0m"
;;
d)
echo -e "\e[1;32m$FILE is a directory file.\e[0m"
;;
l)
echo -e "\e[1;33m$FILE is a link file.\e[0m"
;;
b)
echo -e "\e[1;34m$FILE is a block file.\e[0m"
;;
c)
echo -e "\e[1;35m$FILE is a character file.\e[0m"
;;
s)
echo -e "\e[1;36m$FILE is a socket file.\e[0m"
;;
p)
echo -e "\e[1;37m$FILE is a pipe file.\e[0m"
;;
*)
echo -e "\e[1;31m$FILE is other type file.\e[0m"
esac

4、编写脚本 checkint.sh，判断用户输入的参数是否为正整数

#!/bin/bash
read -p "Please input a digit: " NUM

[[ "$NUM" =~ ^[0-9]+$ ]] && echo -e "\e[1;32m$NUM is a positive integer.\e[0m" || echo -e "\e[1;31m$NUM is not a positive integer.\e[0m"

5、编写脚本 reset.sh，实现系统安装后的初始化环境，包括：1、别名 2、环境变量，如PS1等 3、
安装常用软件包，如：tree 5、实现固定的IP的设置，6、vim的设置等

#!/bin/bash
echo -e "\e[1;31mThis is a system initialization script.\e[0m"
echo -e "\e[1;$[RANDOM%7+31]m"
cat <<EOF
1)禁用SElinux、防火墙
2)安装常用软件包
3)更改yum源
4)修改网卡名和静态地址
5)别名
6)vim设置
7)输入错误，重新选择
EOF
echo -e "\e[0m"

read -p "Please choose a option from menu(1-6): " MENU
case $MENU in
1)
echo -e "\e[1;31mStarting turn off SElinux and Firewalld.\e[0m"
egrep '^SELINUX=' /etc/selinux/config |sed -i 's/enforcing/disabled/' &> /dev/null
setenforce 0 &> /dev/null
systemctl stop firewall &> /dev/null
systemctl disable --now firewall &> /dev/null
echo -e "\e[1;31mTurned off SElinux and firewalld finished.\e[0m"
;;
2)
echo -e "\e[1;32mStarting install many packages.\e[0m"
yum -y install wget vim net-tools
yum -y install psmisc tree bc
echo -e "\e[1;32mInstall packages finished.\e[0m"
;;
3)
echo -e "\e[1;33mStarting update yum resource.\e[0m"
wget -O /etc/yum.repos.d/CentOS-Base.repo https://mirrors.aliyun.com/repo/Centos-8.repio &> /dev/null
yum makecache &> /dev/null
echo -e "\e[1;33mUpdate yum resource finished.\e[0m"
;;
4)
DIR="/etc/sysconfig/network-scripts"
echo -e "\e[1;34mStarting modify network configure.\e[0m"
nmcli connection add type ethernet con-name eth0 ifname ens160 &> /dev/null
nmcli connection delete ens160 &> /dev/null
sed -i 's/ens160/eth0/g' $DIR/ifcfg-eth0  &> /dev/null
sed -i 's/dhcp/static/' $DIR/ifcfg-eth0 &> /dev/null
sed -i '/^GRUB_CMDLINE_LINUX=/s/"$/ net.ifnames=0"/' /etc/default/grub &> /dev/null
grub2-mkconfig -o /boot/grub2/grub.cfg &> /dev/null
echo  "IPADDR=10.0.0.8\nPREFIX=24\nGATEWAY=10.0.0.2" >> $DIR/ifcfg-eth0
echo -e "\e[1;34mModified network configure finished.\e[0m"
;;
5)
echo -e "\e[1;35mStarting define alias name.\e[0m"
alias rm='cp -a /etc /data'
alias cdnet='cd /etc/sysconfig/network-scripts'
alias editnet='vim /etc/sysconfig/network-scripts/ifcfg-eth0'
echo -e "\e[1;35mDefined alias name finished.\e[0m"
;;
6)
echo -e "\e[1;36mStarting configure ~/.vimrc file.\e[0m"
cat /data/vimrc.txt > ~/.vimrc
echo -e "\e[1;37mConfigure ~/.vimrc finished.\e[0m"
;;
*)
echo -e "\e[1;31mInvalid option,please choose again.\e[0m"
;;
esac

练习：用 for 实现
1、判断/var/目录下所有文件的类型

#!/bin/bash
for FILE in $(ls /var);do
TYPE=$(ls -ld /var/$FILE|egrep -o '^.')
case $TYPE in
-)
echo -e "\e[1;31m$FILE is normal file.\e[0m"
;;
d)
echo -e "\e[1;32m$FILE is directory file.\e[0m"
;;
b)
echo -e "\e[1;33m$FILE is block file.\e[0m"
;;
c)
echo -e "\e[1;34m$FILE is character file.\e[0m"
;;
l)
echo -e "\e[1;35m$FILE is link file.\e[0m"
;;
p)
echo -e "\e[1;36m$FILE is pipe file.\e[0m"
;;
S)
echo -e "\e[1;37m$FILE is socket file.\e[0m"
;;
*)
echo -e "\e[1;31m$FILE is other file.\e[0m"
esac
done

2、添加10个用户user1-user10，密码为8位随机字符

#!/bin/bash
for i in `seq 10`;do
if getent passwd user$i &> /dev/null;then
echo -e "\e[1;32muser$i is exist.\e[0m"
else
useradd user$i
PASSWD=`cat /dev/urandom|tr -dc [:alnum:]|head -c8`
echo user${i}:$PASSWD |chpasswd user$i
echo user${i}:$PASSWD >> /data/passwd.txt
echo -e "\e[1;35muser$i created successfully.\e[0m"
fi
done

3、/etc/rc.d/rc3.d目录下分别有多个以K开头和以S开头的文件；分别读取每个文件，以K开头的输出为
文件加stop，以S开头的输出为文件名加start，如K34filename stop S66filename start

#!/bin/bash
FILE=`ls /etc/rc.d/rc3.d/`
for i in FILE;do
find /etc/rc.d/rc3.d/S* -exec mv {} "{} start" \; &> /dev/null
find /etc/rc.d/rc3.d/K* -exec mv {} "{} stop" \; &> /dev/null
done

4、编写脚本，提示输入正整数n的值，计算1+2+…+n的总和

#!/bin/bash``
read -p "Please input a positive integer: " INT
for ((i=1,sum=0;i<=$INT;i++));do
let sum+=i
done
echo -e "\e[1;$[$RANDOM%7+31]mThe sum is $sum.\e[0m"

5、计算100以内所有能被3整除的整数之和

#!/bin/bash
for ((i=1,sum=0;i<=100;i++));do
MODULO=$[i%3]
[ $MODULO -eq 0 ] && let sum+=i
done
echo -e "\e[1;$[$RANDOM%7+31]mThe sum is $sum\e[0m"

6、编写脚本，提示请输入网络地址，如192.168.0.0，判断输入的网段中主机在线状态
版本1：

#!/bin/bash
IP=10.0.0
RED='\e[1;31m'
GREEN='\e[1;32m'
END='\e[0m'

for i in `seq 254`;do
ping -c1 -W1 ${IP}.${i} &> /dev/null && echo -e "${GREEN}${IP}.${i} is up.${END}" || echo -e "${RED}${IP}.${i} is down.${END}"
done

版本2：

#!/bin/bash
IP=10.0.0
RED='\e[1;31m'
GREEN='\e[1;32m'
END='\e[0m'

for ((i=1;i<=254;i++));do
ping -c1 -W1 ${IP}.${i} &> /dev/null && echo -e "${GREEN}${IP}.${i} is up.${END}" || echo -e "${RED}${IP}.${i} is down.${END}"
done

7、打印九九乘法表
版本1：

#!/bin/bash
for i in {1..9};do
for j in `seq $i`;do
echo -e "\e[1;$[RANDOM%7+31]m${j}x${i}=$[i*j]\t\c\e[0m"
done
echo
done

版本2：

#!/bin/bash
for ((i=1;i<=9;i++));do
for ((j=1;j<=i;j++));do
echo -e "\e[1;$[RANDOM%7+31]m${j}x${i}=$[i*j]\t\c\e[0m"
done
echo
done

8、在/testdir目录下创建10个html文件,文件名格式为数字N（从1到10）加随机8个字母，如：
1AbCdeFgH.html

#!/bin/bash
NAME=`cat /dev/urandom|tr -dc '[:alpha:]'|head -c8`
DIR=/data/testdir

for i in `seq 10`;do
if [ -d $DIR ];then
touch ${DIR}/${i}${NAME}.html
else
mkdir -p $DIR
touch ${DIR}/${i}${NAME}.html
fi
done

9、打印等腰三角形

#!/bin/bash
read -p "请输入三角形的行数: " line
for((i=1;i<=line;i++));do
for((k=0;k<=line-i;k++));do
echo -e ' \c'
done
for((j=1;j<=2*i-1;j++));do
echo -e '*\c'
done
echo
done

10、猴子第一天摘下若干个桃子，当即吃了一半，还不瘾，又多吃了一个。第二天早上又将剩下的桃子
吃掉一半，又多吃了一个。以后每天早上都吃了前一天剩下的一半零一个。到第10天早上想再吃时，只
剩下一个桃子了。求第一天共摘了多少？

#!/bin/bash
sum=1
for ((n=1;n<10;n++));do
  sum=$[2*$[$sum+1]]
done
echo "所摘桃子数: $sum"``

练习：用while实现
1、编写脚本，求100以内所有正奇数之和

#!/bin/bash
i=1
sum=0

while ((i<=100));do
let sum+=i
let i+=2
done
echo -e "\e[1;34mThe sum is $sum.\e[0m"

2、编写脚本，提示请输入网络地址，如192.168.0.0，判断输入的网段中主机在线状态，并统计在线和
离线主机各多少

#!/bin/bash
IP=192.168.0

i=1
UP=0
DOWN=0
while [ $i -le 254 ] ;do
if ping -c1 -W1 ${IP}.$i &> /dev/null;then
echo -e "\e[1;32m${IP}.${i} is up.\e[0m"
let UP++
else
echo -e "\e[1;31m${IP}.${i} is down.\e[0m"
let DOWN++
fi
let i++
done
echo -e "\e[1;34mUP is $UP.\e[0m"
echo -e "\e[1;35mDOWN is $DOWN.\e[0m"

3、编写脚本，打印九九乘法表

#!/bin/bash
i=1
while [ $i -le 9 ];do
j=1
while [ $j -le $i ];do
echo -e "\e[1;$[RANDOM%7+31]m${j}x${i}=$[i*j]\t\c\e[0m"
let j++
done
let i++
echo
done

4、编写脚本，利用变量RANDOM生成10个随机数字，输出这个10数字，并显示其中的最大值和最小值

i=1
while true;do
  NUM=$RANDOM
  if [ "$i" -eq "1" ];then
    MAX=$NUM
    MIN=$NUM
  else  
    if [ "$MAX" -lt "${num[$i]}" ];then
      MAX=${num[$i]}
    elif [ "$MIN" -gt "${num[$i]}" ];then
      MIN=${num[$i]}
    else
      true
    fi
  fi
  let i++
done
echo "num is : ${num[@]}"
echo "最大值MAX：$MAX 最小值MIN：$MIN"

5、编写脚本，实现打印国际象棋棋盘

#!/bin/bash
i=1
D_COLOR='\033[1;41m'
S_COLOR='\033[1;47m'
AND_COLOR='\033[0m'
while [ $i -le 8 ];do
  if [ "$[$i%2]" -eq "0" ];then
    j=1
    while [ $j -le 8 ];do
      if [ "$[$j%2]" -eq "0" ];then
        echo -e "${S_COLOR} ${AND_COLOR}\c"
      else
        echo -e "${D_COLOR} ${AND_COLOR}\c"
      fi
      let j++
    done
  else
    j=1
    while [ $j -le 8 ];do
      if [ "$[$j%2]" -eq "0" ];then
        echo -e "${D_COLOR} ${AND_COLOR}\c"
      else
        echo -e "${S_COLOR} ${AND_COLOR}\c"
      fi
      let j++
    done
  fi
  echo ""
  let i++
done

6、后续六个字符串：efbaf275cd、4be9c40b8b、44b2395c46、f8c8873ce0、b902c16c8b、
ad865d2f63是通过对随机数变量RANDOM随机执行命令： echo $RANDOM|md5sum|cut -c1-10
后的结果，请破解这些字符串对应的RANDOM值

#!/bin/bash
RAN=1
cat test.txt | while read CHESS;do
  { while true;do
    MD=echo $RAN|md5sum|cut -c1-10
    if [[ "$MD" == "$CHESS" ]];then
      echo $RAN
      break
    else
      let RAN++
    fi
  done }&
  wait
done

练习
1、每隔3秒钟到系统上获取已经登录的用户的信息；如果发现用户hacker登录，则将登录时间和主机记
录于日志/var/log/login.log中,并退出脚本

#!/bin/bash
while :;do
who|grep 'hacker' >> /var/log/login.log
sleep 3
done

2、随机生成10以内的数字，实现猜字游戏，提示比较大或小，相等则退出

#!/bin/bash
NUM1=`cat /dev/urandom|tr -dc '[:digit:]'|head -c1`
while :;do
read -p "Please input a digit[0-9]: " NUM2
if [ $NUM2 -eq $NUM1 ];then
echo -e "\e[1;$[RANDOM%7+31]mCongratulations, got it right.\e[0m"
exit 2
elif [ $NUM2 -lt $NUM1 ];then
echo -e "\e[1;$[RANDOM%7+31]mSorry,is too lower.\e[0m"
else
echo -e "\e[1;$[RANDOM%7+31]mSorry,is too higher.\e[0m"
fi
done

3、用文件名做为参数，统计所有参数文件的总行数

#!/bin/bash
read -p "Please input a little filename: " FILES
while [ -n "$FILES" ];do
echo -e "\e[1;33mLines are `cat $FILES |wc -l`.\e[0m"
break
done

4、用二个以上的数字为参数，显示其中的最大值和最小值

#!/bin/bash
if [ $# -lt 2 ];then
echo at least 2 argument
exit 1
fi

declare -i big
declare -i small
declare -i fir=$#
until [ $# = 0 ];do
if [[ ! "$1" =~ ^[0-9]+$ ]];then
echo wrong number $1
exit
fi
if [ $fir = $# ];then
let big=$1
let small=$1
else
if [ $1 -gt $big ];then
let big=$1
elif [ $1 -lt $small ];then
let small=$1
fi
fi
shift
done
echo the biggest number is : $big
echo the smallest unmber is: $small