while练习题
1、求100以内所有正整数之和 2、通过ping命令探测172.16.250.1 - 254范围内的所有主机的在线状态，统计在线主机和离线主机各多少。 3、打印九九乘法表 4、利用变量RANDOM生成10个随机数字，输出这个10数字，并显示其中的最大者和最小者 5、打印国际象棋棋盘
答案
答案一
[root@centos7 bin]#
[root@centos7 bin]# cat 100sunwhile.sh
#!/bin/bash
declare -x i
i=1
while [ $i -le 100 ];do
let sum+=$i
let i++
done
echo "1~100sum is :$sum"
[root@centos7 bin]#
答案二
[root@centos7 bin]# cat hostpingwhile.sh
#!/bin/bash
declare -i i=0
declare -i j=0
ip=10.1.252.
declare -i ip2=218
while [ $ip2 -le 254 ];do
if ping -c1 -w1 $ip$ip2 &>/dev/null;then
let i++
echo "$ip$ip2 host is online"
else
let j++
echo "$ip$ip2 host is not online"
fi
let ip2++
done
echo "the number of online host is :$i "
echo "the number of no online host is :$j "
[root@centos7 bin]#
答案三
[root@centos7 bin]# cat chengfabiaowhile.sh
#!/bin/bash
declare -i i=1
while [ $i -le 9 ] ;do
declare -i j=1
while [ $j -le $i ];do
echo -e " $j*$i=$[ $i*$j ]\c"
let j++
done
let i++
echo -e "\n"
done
[root@centos7 bin]#
答案四
[root@centos7 bin]# cat Random.sh
#!/bin/bash
declare -i i=1
while [ $i -le 10 ];do
let random=$RANDOM%80
echo "the $i shu is :$random"
if [ $i -eq 1 ]
then
max=$random
min=$random
elif [[ $random -gt $max ]]
then
max=$random
elif [[ $random -lt $min ]]
then
min=$random
fi
let i+=1
done
echo "the max values is:$max"
echo "the min values is:$min"
[root@centos7 bin]#
答案5
[root@centos7 bin]# cat xiangqi.sh
#!/bin/bash
for n in `seq 1 8`;do
for m in `seq 1 4`;do
case $n in
1|3|5|7)
echo -e "\033[41m \033[0m\c"
echo -e "\033[47m \033[0m\c"
;;
*)
echo -e "\033[47m \033[0m\c"
echo -e "\033[41m \033[0m\c"
;;
esac
done
echo ""
done
[root@centos7 bin]#
[root@centos7 bin]# cat xiangqi2.sh
#!/bin/bash
for i in {1..8};do
for j in {1..8};do
if [ $[$i%2] -eq 0 ];then
echo -ne "\033[41m \033[m"
else
echo -ne "\033[42m \033[m"
fi
let i++
done
echo
done
echo "$j"
[root@centos7 bin]#
while特殊用法练习
1、扫描/etc/passwd文件每一行，如发现注释字段为空，则填充用户名和单位电话为62985600，并提示该用户的GECOS（注释）信息修改成功。 [root@centos7 until]# cat whileReadP.sh #!/bin/bash while read passwd ;do content=`echo $passwd |cut -d : -f5` username=`echo $passwd |cut -d: -f1` if [[ -z $content ]];then chfn -f "$username" $username &> /dev/null chfn -p "10086" $username &>/dev/mull fi done < /etc/passwd [root@centos7 until]# 2、将上题的添加清空 [root@centos7 until]# cat whileReadP.sh #!/bin/bash while read passwd ;do content=`echo $passwd |cut -d : -f5` username=`echo $passwd |cut -d: -f1` if [[ -n $content ]];then chfn -f "" $username &> /dev/null chfn -p "" $username &>/dev/mull fi done < /etc/passwd [root@centos7 until]#
until 循环
until CONDITION; do 循环体 done 进入条件： CONDITION 为false 退出条件： CONDITION 为true
until练习题
1、每隔3秒钟到系统上获取已经登录的用户的信息；如果发现用户hacker登录，则将登录时间和主机记录于日志/var/log/login.log中,并提示该用户退出系统。
2、随机生成10以内的数字，实现猜字游戏，提示比较大或小，相等则退出
3、编写脚本，求100以内所有正整数之和
4、编写脚本，通过ping命令探测172.16.250.1-254范围内的所有主机的在线状态，统计在线主机和离线主机各多少。
5、编写脚本，打印九九乘法表
6、编写脚本，利用变量RANDOM生成10个随机数字，输出这个10数字，并显示其中的最大者和最小者
7、编写脚本，实现打印国际象棋棋盘
8、用*打印等腰三角形
答案：
答案1
[root@centos7 until]# cat userlogininfo.sh
#!/bin/bash
#name:wangnannan
#time:2010816
#description:checking the user longin information
echo "check start"
until false;do
sleep 3
if who |grep hacker &>/dev/null;then
who |tr -s " " |cut -d " " -f1,3,4 >> /var/log/login.log
echo -e "find hackernlogin and /var/log/login.log have record ."
echo "please hacker loginout " |write hacker
else
echo "not find hacker"
fi
done
[root@centos7 until]#
答案二、
[root@centos7 until]# cat guess.sh
#!/bin/bash
#name:wangnannan
#description:guess the Random
let random=$RANDOM%11
until false ;do
read -p "please you guess the Random[1-10] :" num
if let $num+0 ;then
if [ $num -gt $random ];then
echo "you input greater then random"
elif [ $num -lt $random ];then
echo "you input lesser then random"
elif [ $num -eq $random ];then
echo "you guess ok"
break
fi
else
echo "plese input a inter"
fi
done
[root@centos7 until]#
答案三
[root@centos7 until]#
[root@centos7 until]# cat 100sum.sh
#!/bin/bash
#name:wangnannan
#description:caculate 1-100 sum
declare -i i=1
until [ $i -gt 100 ] ;do
let sum+=i
let i++
done
echo "sum is :$sum"
[root@centos7 until]#
答案四
[root@centos7 until]# cat hostping.sh
#!/bin/bash
declare -i i=0
declare -i j=0
read -p "please the ip ：" ip
if echo $ip |egrep -q "^(([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5]).){3}([0-9]|[1-9][0-9]|1[0-9][0-9]| 2[0-4][0-9]|25[0-5])$";then
ipv=`echo "$ip" | cut -d . -f 1,2,3`
declare -i ip2=1
until [ $ip2 -gt 5 ];do
if ping -c1 -w1 $ipv.$ip2 &>/dev/null;then
let i++
echo "$ipv.$ip2 host is online"
else
let j++
echo "$ipv.$ip2 host is not online"
fi
let ip2++
done
echo "the number of online host is :$i "
echo "the number of no online host is :$j "
else
echo "input ip error"
fi
[root@centos7 until]#
答案五
[root@centos7 until]# cat chengfabiao
#!/bin/bash
#name:wangnannan
#description:output chengfabiao
declare -i i=1
until [ $i -gt 9 ];do
declare -i j=1
until [ $j -gt $i ];do
echo -ne "$j*$i=$[i*j]\t"
let j++
done
echo 换行输出
let i++
done
[root@centos7 until]#
答案六
[root@centos7 until]# cat random.sh
#!/bin/bash
#name：wangnannan
#description：generate ten random numbers and find the maximum and minimum values
i=9
max=$[$RANDOM%10]
min=$max
echo "the random is:$max"
until [ $i -le 0 ];do
random=$[$RANDOM%10]
echo "the random is:$random"
let i--
if [ $random -ge $max ];then
max=$random
elif [ $random -lt $min ];then
min=$random
fi
done
echo "the maximum is:$max"
echo "the minimum is:$min"
[root@centos7 until]#
答案七：
[root@centos7 until]# cat chessBoard.sh
#!/bin/bash
#name:wangnannan
#description:output chess board
i=1
until [ $i -gt 9 ];do
j=1
until [ $j -gt 9 ];do
m=$[(i+j)%2]
if [ $m -eq 0 ];then
echo -ne "\033[47m \033[0m"
elif [ $m -eq 1 ];then
echo -ne "\033[41m \033[0m"
fi
let j++
done
let i++
echo
done
[root@centos7 until]#
答案八
正三角
[root@centos7 until]#
[root@centos7 until]# cat iT.sh
#!/bin/bash
#name:wangnannan
#description：output a isosceles triangle ues *
read -p "please input a number n, I,ll output n hang isosceles triangle:" n
until [[ $n =~ ^[[:digit:]]+$ ]];do
echo -e "\033[32myour input is not a interger\nplesea chongxin input\033[m"
read -p "please input a number n, I,ll output n hang isosceles triangle:" n
done
i=0
until [ $i -ge $n ];do
j=0
x=0
until [ $x -ge $[n-(i+1)] ];do
echo -n " "
let x++
done
until [ $j -ge $[2*i+1] ];do
echo -ne "\033[31m*\033[m"
let j++
done
let i++
echo
done
[root@centos7 until]#
倒三角
[root@centos7 until]# cat riT.sh
#!/bin/bash
#name:wangnannan
#description:oupput a triangle
read -p "plese input a n:" n
i=0
until [ $i -ge $n ];do
h=0
until [ $h -ge $i ];do
echo -n " "
let h++
done
j=0
until [ $j -ge $[2*(n-i)-1] ];do
echo -ne "\033[32m*\033[m"
let j++
done
let i++
echo
done
[root@centos7 until]#
原创文章，作者：wangnannan，如若转载，请注明出处：http://www.178linux.com/36989
