1、打印九九乘法表

方法一

#外层循环表示9行for row in `seq 9`do        #里层循环表示列        for col in `seq $row`        do                echo -e $row x $col =  "$[ row*col ]\t\c"        done        echo done

方法二：

for((i=1;i<=9;i++));do for((j=1;j<=i;j++));do echo -ne "$j X $i = $((i*j))\t";done;echo;done;

方法三：awk写法

awk 'BEGIN{for(i=1;i<=9;i++){for(j=1;j<=i;j++){printf "%s %-4d","j x i =",i*j}printf "\n"}}'

2、国际象棋棋盘

#输入1为两个空格read -p "输入每个方格的大小(2space=1)：" weight#八行国际象棋for i in `seq 8`;do        for j in `seq $weight`;do                #奇数行为红 绿 红 绿  ....                 if [ "$[i%2]" = 1 ];then                        colour1=41  #红色                        colour2=42  #绿色                else #偶数行为 绿红 绿红 ....                        colour1=42                        colour2=41                fi                for k in `seq 4`;do #每行8个方块                        for n in `seq $weight`;do  #打印2个方块                                echo -ne "\033[${colour1}m  \033[0m"                        done                        for m in `seq $weight`;do  #打印2个方块                                echo -ne "\033[${colour2}m  \033[0m"                        done                done                echo

3、打印等腰三角形

read -p "请输入三角形的行数:" linefor i in `seq $line`do        space=`echo $[line-i]`        for j in `seq $space`        do                echo -n ' '        done        for k in `seq $[$i*2-1]`        do                echo -n '*'        done        echodone

4、打印下图

num=9for i in `seq 1 $num`;do        let j=2*$i-1        let m=10-$i        for l in `seq 1 $m` ;do                echo -e " \c"        done        for k in `seq 1 $j`;do                let n=$i%2                if [ $n -eq 0 ];then                  echo -ne "\e[1;5;3$[i]m$i\e[0m"                elif [[ $k -eq 1||$k -eq $j ]];then                  echo -ne "\e[1;5;3$[i]m$i\e[0m"                else                  echo -ne "\e[1;3$[i]m$i\e[0m"                fi        done        echodoneunset iunset junset kunset llet j=$num/2-1for i in `seq 1 $j`;do        echo -e "\e[1;3$[i]m        666\\e[0m"doneecho -e "\e[1;34m       66666\\e[0m"

5、打印下图

#输入三角形边长（n个*）read -p "Please input the triangle side " n#遍历n行三角形for i in `seq $n`do                #打印空格        for j in `seq $[n-i]`        do                echo -e " \c"        done                #除第一行外打印一个星号        if [[ "$i" -ne 1 ]]; then        echo -e "*\c"        fi                #除第一行和最后一行打印空格        if [[ "$i" -ne 1 && "$i" -ne "$n" ]]; then        {                for k in `seq $[2*(i-1) -1]`                do                echo -e " \c"                done        }        fi                #最后一行打印星号        if [[ "$i" -eq "$n"  ]]; then        {                k=0                for k in `seq $[2*i-3]`                do                        echo -e "*\c"                done        }        fi        echo -e "*"done

6、每隔30秒监控httpd服务是否启动，如果没启动就启动httpd服务

sleeptime=30while truedo        if killall -0 httpd &> /dev/null;then                true        else                systemctl restart httpd                time=`date +"%F %T" `                echo "httpd service at "$time" is restarted" >> /app/http.log        fi        sleep "$sleeptime"done

让脚本在后台执行不影响前台正常工作

nohup ./root/scripts/monhttpd.sh &

7、将连接服务器次数很多次的客户端IP加入防火墙

while truedo        ss -nt | grep ESTAB | tr -s " " ":" | cut -d: -f6 | sort | uniq -c | while read num ip         do                if [ "$num" -gt 2 ];then                iptables -A INPUT -s "$ip" -j REJECT                fi        done        sleep 3done

8、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

i=1while [ "$i" -le 32767 ];do        ranmd5=`echo $i | md5sum | cut -c1-10`        case ${ranmd5}  in                efbaf275cd)                        echo $i md5 is efbaf275cd                        ;;                4be9c40b8b)                        echo $i md5 is 4be9c40b8b                         ;;                44b2395c46)                        echo $i md5 is 4be9c40b8b                        ;;                f8c8873ce0)                        echo $i md5 is 4be9c40b8b                        ;;                b902c16c8b)                        echo $i md5 is 4be9c40b8b                        ;;                ad865d2f63)                        echo $i md5 is 4be9c40b8b                        ;;        esac        let i++;done

9、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（随机数最大值32767）

i=1while [ "$i" -le 10 ];do        random=`echo $RANDOM`        echo $random        if [ "$i" = 1 ];then                max=$random                min=$random        else                if [ "$random" -gt "$max"  ];then                        max="$random"                elif [ "$random" -lt "$min" ];then                        min="$random"                fi        fi        let i+=1doneecho "max is $max"echo "min is $min"

10、while循环创建菜单

cat <

select 循环主要用于创建菜单，按数字顺序排列的菜单项将显示在标准错误上，并显示 PS3 提示符，等待用户输入

PS3="please input a menu number: "        select num in huimian mers jdt jikuai quit;do                reply=`echo $REPLY`                echo "---------  $reply"                case "$reply" in                1|2|huimian|mers)                         echo "The price is 15"                         ;;                3|jdt)                        echo "The price is 50"                        ;;                4|jikuai)                        echo "The is is 30"                        ;;                5)                        break                        ;;                *)                                                echo "your input is $reply"                        echo "please input again "                        ;;                esac        done

11、求100以内所有奇数之和

for ((sum=0,i=1;i<100;i+=2));do let sum+=i;done;echo $sum

12、求100以内所有能被3整除的数之和

sum=0;i=0;while [ $i -lt 100 ];do let sum+=i;let i+=3;done; echo $sum

13、随机生成10以内的数字，实现猜字游戏，提示比较大或小，相等则退出方法一

random=`echo $[RANDOM%10]`read -p "please guess a num: " numwhile [ $num -ne $random ];do        if [ $num -gt $random ];then                echo "your num is too big"                read -p "please guess a num again: " num        elif [ $num -lt $random ];then                echo "your num is too small"                read -p "please guess a num again : " num        fidoneecho -e "\033[31mcongratulation! \033[31m"

方法二