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

1#!/bin/bash
2YELLOW='\e[1;33m'
3RED='\e[1;31m'
4END='\e[0m'
5
6echo -e "${YELLOW}++++++++++++++++++++++++++++++++++++++++++${END}"
7echo -e "${RED}HOSTNAME:        `hostname`${END}"
8echo -e "${RED}IPADDR:          `hostname -I`${END}"
9echo -e "${RED}OS's version:    `cat /etc/centos-release`${END}"
10echo -e "${RED}Kernel version:  `uname -r`${END}"
11echo -e "${RED}CPU:            `lscpu |egrep '^Model name'|tr -s ' '|cut -d: -f2`${END}"
12echo -e "${RED}Memory size:     `free -h|sed -rn '2p'|tr -s ' '|cut -d' ' -f2`${END}"
13echo -e "${RED}Disk size:       `lsblk |sed -n '2p'|egrep -o '([0-9]+)G'`${END}"
14echo -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：

1#!/bin/bash
2RED='\e[1;31m'
3GREEN='\e[1;32m'
4END='\e[0m'
5SOURCE="/etc"
6DEST="/backup"
7
8[ ! -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：

1#!/bin/bash
2RED='\e[1;31m'
3GREEN='\e[1;32m'
4END='\e[0m'
5SOURCE="/etc"
6DEST="/backup"
7
8if [ ! -d $DEST ];then
9  mkdir $DEST
10  echo -e "${RED}Start backup...${END}"
11  sleep 3
12  cp -av $SOURCE $DEST/etc`date +%F`
13  echo -e "${GREEN}Back is finished.${END}"
14else
15  echo -e "${RED}Start backup...${END}"
16  sleep 3
17  cp -av $SOURCE $DEST/etc`date +%F`
18  echo -e "${GREEN}Back is finished.${END}"
19fi

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

1#!/bin/bash
2COLOR='\e[1;36m'
3END='\e[0m'
4MAX=`df|egrep '^/dev/sd'|egrep -o '([0-9]+)%' |tr -d '%'|sort -nr|head -1`
5
6echo -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

1#!/bin/bash
2COLOR='\e[1;34m'
3END='\e[0m'
4RESULT=`netstat -tan|egrep 'ESTABLISHED'|tr -s ' ' :|cut -d: -f6|sort|uniq -c|sort -nr`
5
6echo -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：

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

版本2：

1#!/bin/bash
2if [ $# -lt 1 ];then
3  echo -e "\e[1;31mPlease at least input a filename as an argument.\e[0m"
4  exit 2
5else
6  echo -e "\e[1;36mBlank line is `egrep '^$' $1 $2 $3 | wc -l`.\e[0m"
7fi  

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：

1#!/bin/bash
2IP=10.0.0.7
3RED='\e[1;31m'
4GREEN='\e[1;32m'
5ping -c1 -W1 $IP &> /dev/null && echo -e "${GREEN}${IP} is up.${END}" || echo -e "${RED}${IP} is down.${END}"

版本2：

1#!/bin/bash
2RED='\e[1;31m'
3GREEN='\e[1;32m'
4END='\e[0m'
5IP=10.0.0.2
6if ping -c1 -W1 $IP &> /dev/null;then
7  echo -e "${GREEN}${IP} is up.${END}"
8else
9  echo -e "${RED}${IP} is down.${END}"
10fi  

版本3：

1#!/bin/bash
2IP=10.0.0
3RED='\e[1;31m'
4GREEN='\e[1;32m'
5END='\e[0m'
6
7for i in `seq 254`;do
8  ping -c1 -W1 ${IP}.${i} &> /dev/null && echo -e "${GREEN}${IP}.${i} is up.${END}" || echo -e "${RED}${IP}.${i} is down.${END}"
9done

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：

1#!/bin/bash
2WARN=20
3GREEN='\e[1;32m'
4END='\e[0m'
5SPACE_USED=`df|egrep '^/dev/sd'|egrep -o '([0-9]+)%' |tr -d '%'|sort -nr|head -1`
6INODE_USED=`df -i|egrep '^/dev/sd'|egrep -o '([0-9]+)%' |tr -d '%'|sort -nr|head -1`
7
8[ $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：

1#!/bin/bash
2WARN=20
3YELLOW='\e[1;33m'
4END='\e[0m'
5DISK_USED=`df|egrep '/dev/sd'|egrep -o '([0-9]+)%'|tr -d '%'|sort -nr|head -1`
6INODE_USED=`df -i|egrep '^/dev/sd'|egrep -o '([0-9]+)%' |tr -d '%'|sort -nr|head -1`
7
8if [ $DISK_USED -ge $WARN -o $INODE_USED -ge $WARN ];then
9  echo "Disk space will be full." |mail -s Diskwarning 123456789@qq.com
10else
11  echo -e "${YELLOW}Disk space is enough.${END}"
12fi 

版本3：

1#!/bin/bash
2WARN=10
3RED='\e[1;31m'
4BLUE='\e[1;34m'
5END='\e[0m'
6
7DISK_USED=`df|egrep '^/dev/sd'|egrep -o '([0-9]+)%' |tr -d '%'`
8
9for i in $DISK_USED;do
10  [ $i -ge $WARN ] && echo -e "${RED}Disk space will be full.${END}" || echo -e "${BLUE}Disk space is enough.${END}"
11done

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：

1#!/bin/bash
2read -p "Please input a filename: " FILE
3[ ! -r $FILE -a ! -w $FILE ] && echo "$FILE is not readable and not writeable" || echo "$FILE is readable or writeable."

版本2：

1#!/bin/bash
2COLOR1='\e[1;33m'
3COLOR2='\e[1;34m'
4END='\e[0m'
5if [ $# -ne 0 ];then
6  [ ! -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}"
7else
8  echo -e "${COLOR1}Please input a file.${END}"
9fi

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：

1#!/bin/bash
2RED='\e[1;31m'
3YELLOW='\e[1;33m'
4END='\e[0m'
5read -p "Please input a filename: " FILE
6[[ "$FILE" =~ ^.*\.sh$ ]] && { 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：

1#!/bin/bash
2RED='\e[1;31m'
3YELLOW='\e[1;33m'
4END='\e[0m'
5read -p "Please input a filename: " FILE
6if [[ "$FILE" =~ ^.*\.sh$ ]];then
7  chmod a+x $FILE
8  echo -e "${YELLOW}${FILE}'s executeable permission is added.${END}"
9else
10  echo -e "${RED}${FILE} is not a script file.${END}"
11fi 

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：

1#!/bin/bash
2YELLOW='\e[1;33m'
3END='\e[0m'
4FILE="/etc/nologin"
5
6[ ! -e $FILE ] && { touch $FILE; echo -e "${YELLOW}Prohibit common user login.${END}"; } || echo -e "${YELLOW}Cmmon user can not login.${END}"

版本2：

1#!/bin/bash
2YELLOW='\e[1;33m'
3RED='\e[1;31m'
4END='\e[0m'
5FILE="/etc/nologin"
6
7if [ ! -e $FILE ];then
8  touch $FILE 
9  echo -e "${YELLOW}Prohibit common user login.${END}"
10else  
11  echo -e "${RED}Cmmon user can not login.${END}"
12fi

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

1echo "export PATH=/usr/local/apache/bin:$PATH" >> /etc/profile
2source /etc/profile
3echo $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)

1echo 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
2cat <<EOF >> ~/.bashrc
3>rm='rm -i'
4>cdnet='cd /etc/sysconfig/network-scripts/'
5>editnet='vim /etc/sysconfig/network-scripts/ifcfg-eth0'
6>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

1vim ~/.vimrc
2set ts=2
3set expandtab
4set ignorecase
5set autoindent
6autocmd BufNewFile *.sh exec ":.call SetTitle()"
7func SetTitle()
8if expand("%:e") == 'sh'
9    call setline(1,"#!/bin/bash")
10    call setline(2,"#***********************************************")
11    call setline(3,"#Author:         Kingdom_xu")
12    call setline(4,"#Mail:           123456789@qq.com")
13    call setline(5,"#Version:        1.0")
14    call setline(6,"#Date:           ".strftime("%Y-%m-%d"))
15    call setline(7,"#FileName:       ".expand("%"))
16    call setline(8,"#Description:    The test script")
17    call setline(9,"#Copyright (C):  ".strftime("%Y")." All rights reserved")
18    call setline(10,"#***********************************************")
19    call setline(11,"")
20endif
21endfunc
22autocmd 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：

1#!/bin/bash
2read -p "Please input a username: " NAME
3
4[ -z $NAME ] && { echo -e "\e[1;33mPlease give a username.\e[0m";exit 2; }
5id $NAME &> /dev/null && { echo -e "\e[1;36m$NAME is exist.\e[0m"; } || { useradd $NAME;echo $NAME:123456 | chpasswd $NAME;getent passwd $NAME;passwd -e $NAME &> /dev/null; }

版本2：

1#!/bin/bash
2read -p "Please input a username: " NAME
3
4if [ -z $NAME ];then
5  echo -e "\e[1;37mInput a username.\e[0m"
6  exit 2
7fi
8
9if getent passwd $NAME;then
10  echo -e "\e[1;32m$NAME is exist.\e[0m"
11else
12  useradd $NAME
13  echo $NAME:123456 | chpasswd $NAME
14  id $NAME 
15  passwd -e $NAME &> /dev/null
16fi

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

1#!/bin/bash
2read -p "Please input yes or no: " ANS
3
4case $ANS in
5[Yy]|[Yy][Ee][Ss])
6  echo -e "\e[1;34mYour answer is YES.\e[0m"
7  ;;
8[Nn]|[Nn][Oo])
9  echo -e "\e[1;35mYour answer is NO.\e[0m"
10  ;;
11*)
12  echo -e "\e[1;33mPlease input yse or no.\e[0m"
13esac

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）

1#!/bin/bash
2read -p "Input a filename: " FILE
3TYPE=`ls -ld $FILE|egrep -o '^.'`
4
5case $TYPE in
6-)
7  echo -e "\e[1;31m$FILE is a normal file.\e[0m"
8  ;;
9d)
10  echo -e "\e[1;32m$FILE is a directory file.\e[0m"
11  ;;
12l)
13  echo -e "\e[1;33m$FILE is a link file.\e[0m"
14  ;;
15b)  
16  echo -e "\e[1;34m$FILE is a block file.\e[0m"
17  ;;
18c)  
19  echo -e "\e[1;35m$FILE is a character file.\e[0m"
20  ;;
21s)
22  echo -e "\e[1;36m$FILE is a socket file.\e[0m"
23  ;;
24p)
25  echo -e "\e[1;37m$FILE is a pipe file.\e[0m"
26  ;;
27*)
28  echo -e "\e[1;31m$FILE is other type file.\e[0m"
29esac

4、编写脚本 checkint.sh，判断用户输入的参数是否为正整数

1#!/bin/bash
2read -p "Please input a digit: " NUM
3
4[[ "$NUM" =~ ^[0-9]+$ ]] && 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

1#!/bin/bash
2echo -e "\e[1;31mThis is a system initialization script.\e[0m"
3echo -e "\e[1;$[RANDOM%7+31]m"
4cat <<EOF
51)禁用SElinux、防火墙
62)安装常用软件包
73)更改yum源
84)修改网卡名和静态地址
95)别名
106)vim设置
117)输入错误，重新选择
12EOF
13echo -e "\e[0m"
14
15read -p "Please choose a option from menu(1-6): " MENU
16case $MENU in
171)
18  echo -e "\e[1;31mStarting turn off SElinux and Firewalld.\e[0m"
19  egrep '^SELINUX=' /etc/selinux/config |sed -i 's/enforcing/disabled/' &> /dev/null
20  setenforce 0 &> /dev/null
21  systemctl stop firewall &> /dev/null
22  systemctl disable --now firewall &> /dev/null
23  echo -e "\e[1;31mTurned off SElinux and firewalld finished.\e[0m"
24  ;;
252)
26  echo -e "\e[1;32mStarting install many packages.\e[0m"
27  yum -y install wget vim net-tools
28  yum -y install psmisc tree bc
29  echo -e "\e[1;32mInstall packages finished.\e[0m"
30  ;;
313)
32  echo -e "\e[1;33mStarting update yum resource.\e[0m"
33  wget -O /etc/yum.repos.d/CentOS-Base.repo https://mirrors.aliyun.com/repo/Centos-8.repio &> /dev/null
34  yum makecache &> /dev/null
35  echo -e "\e[1;33mUpdate yum resource finished.\e[0m"
36  ;;
374)
38  DIR="/etc/sysconfig/network-scripts"
39  echo -e "\e[1;34mStarting modify network configure.\e[0m"
40  nmcli connection add type ethernet con-name eth0 ifname ens160 &> /dev/null
41  nmcli connection delete ens160 &> /dev/null
42  sed -i 's/ens160/eth0/g' $DIR/ifcfg-eth0  &> /dev/null
43  sed -i 's/dhcp/static/' $DIR/ifcfg-eth0 &> /dev/null 
44  sed -i '/^GRUB_CMDLINE_LINUX=/s/"$/ net.ifnames=0"/' /etc/default/grub &> /dev/null
45  grub2-mkconfig -o /boot/grub2/grub.cfg &> /dev/null
46  echo  "IPADDR=10.0.0.8\nPREFIX=24\nGATEWAY=10.0.0.2" >> $DIR/ifcfg-eth0
47  echo -e "\e[1;34mModified network configure finished.\e[0m"
48  ;;
495)
50  echo -e "\e[1;35mStarting define alias name.\e[0m"
51  alias rm='cp -a /etc /data'
52  alias cdnet='cd /etc/sysconfig/network-scripts'
53  alias editnet='vim /etc/sysconfig/network-scripts/ifcfg-eth0'
54  echo -e "\e[1;35mDefined alias name finished.\e[0m"
55  ;;
566)
57  echo -e "\e[1;36mStarting configure ~/.vimrc file.\e[0m"
58  cat /data/vimrc.txt > ~/.vimrc 
59    echo -e "\e[1;37mConfigure ~/.vimrc finished.\e[0m"
60    ;;
61*)
62    echo -e "\e[1;31mInvalid option,please choose again.\e[0m"
63  ;;
64esac