一、if语句、while、for循环各种小例题
1.用户验证
[root@bogon ~]# cat buer.sh #!/bin/bash #user='buer' #password='1234.com' read -p 'please your name:' user read -p 'password:' passwd if [ $user = 'buer' -a $passwd = '1234.com' ];then echo 'login successful' fi
2.猜年龄
#!/bin/bash age=57 read -p 'num:' num if [ $num -eq $age ];then echo 'you get it' elif [ $num -gt $age ];then echo 'too big' elif [ $num -lt $age ];then echo 'too samll' fi
3.查询成绩
[root@bogon ~]# cat score.sh #!/bin/bash read -p 'please your score:' score if [ $score -ge 90 ];then echo 'very good!' elif [ $score -ge 70 -a $score -lt 90 ];then echo 'good!' elif [ $score -ge 60 -a $score -lt 70 ];then echo 'just like' else echo 'poor' fi
4.for循环打印1235
[root@bogon ~]# cat for.sh #!/bin/bash for i in {1..5} do if ((i == 4));then continue #break fi echo '=======' $i done
脚本4的执行结果：
[root@bogon ~]# ./for.sh ======= 1 ======= 2 ======= 3 ======= 5
5.改进版的猜年龄
[root@bogon ~]# cat oldboy.sh oldboy=57 while : do read -p 'input your age:' age if [ -z $age ];then continue fi if [ $age -eq $oldboy ];then echo "bingo" break elif [ $age -lt $oldboy ];then echo "little" elif [ $age -gt $oldboy ];then echo "big" else echo "bye" fi done
脚本5结果：
[root@bogon ~]# ./oldboy.sh input your age:45 too samll input your age:65 too big input your age:57 you get it [root@bogon ~]#
6.查看文件类型
[root@bogon ~]# cat aa.sh #!/bin/bash while : do read -p 'input your file:' file if [ -z $file ];then continue elif [ $file = 'quit' ];then break fi if [ -b $file ];then echo "$file is block file" elif [ -d $file ];then echo "$file is directory file" elif [ -f $file ];then echo "$file is regular file" else echo "$file unkown" fi done
脚本6结果：
[root@bogon ~]# sh aa.sh input your file:/etc /etc is directory file input your file:/pm /pm unkown input your file:quit
7.打印乘法口诀表
[root@bogon ~]# cat cheng.sh #!/bin/bash for ((i=1;i<=9;i++)) do for ((j=1;j<=i;j++)) do echo -n "$i*$j=$[$i*$j]" done echo done
脚本7结果：
[root@bogon ~]# ./cheng.sh 1*1=1 2*1=22*2=4 3*1=33*2=63*3=9 4*1=44*2=84*3=124*4=16 5*1=55*2=105*3=155*4=205*5=25 6*1=66*2=126*3=186*4=246*5=306*6=36 7*1=77*2=147*3=217*4=287*5=357*6=427*7=49 8*1=88*2=168*3=248*4=328*5=408*6=488*7=568*8=64 9*1=99*2=189*3=279*4=369*5=459*6=549*7=639*8=729*9=81
8.批量创建用户
[root@bogon ~]# cat add.sh #!/bin/bash for i in {1..5}; do useradd user$i && echo "user$i create successful" done
脚本8执行结果：
[root@bogon ~]# sh add.sh user1 create successful user2 create successful user3 create successful user4 create successful user5 create successful
9.批量删除用户
[root@bogon ~]# cat del.sh #!/bin/bash for i in {1..5}; do userdel -r user$i && echo "user$i delete successful" done
脚本9执行结果：
[root@bogon ~]# sh del.sh user1 delete successful user2 delete successful user3 delete successful user4 delete successful user5 delete successful
10.循环叠加打印数字，并睡眠1s
[root@bogon ~]# cat conut.sh #!/bin/bash count=1 while ((count < 10)) do echo '==========>' $count sleep 1 ((count+=1)) done
执行结果：
[root@bogon ~]# sh conut.sh ==========> 1 ==========> 2 ==========> 3 ==========> 4 ==========> 5 ==========> 6 ==========> 7 ==========> 8 ==========> 9
11.批量ping ip
[root@bogon ~]# cat ping.sh #!/bin/bash for i in {1..100}; do ping -c1 192.168.16.$i &> /dev/null if [ $? -eq 0 ];then echo "192.168.16.$i OK" echo "192.168.16.$i" >> /tmp/ip.txt fi done
12.模仿登录用户小工具
[root@bogon ~]# cat login.sh #!/bin/bash user='buer' passwd='1234.com' while $tag do read -p 'input your name:' name read -p 'input your passwd:' pas if [[ $name = $user ]] && [[ $pas = $passwd ]];then echo 'login successful' while $tag do read -p '>>:' cmd if [[ $cmd = 'quit' ]];then tag=false else $cmd fi done fi done
执行结果：
[root@bogon ~]# sh login.sh input your name:buer input your passwd:1234.com login successful >>:ls aa.sh a.txt del.sh oldboy.sh 模板 下载 add.sh buer.sh for.sh ping.sh 视频 音乐 age.sh cheng.sh initial-setup-ks.cfg score.sh 图片 桌面 anaconda-ks.cfg conut.sh login.sh 公共 文档 >>:pwd /root >>:quit [root@bogon ~]#