shell学习之路:流程控制(for)

for循环的语法:

1. for 变量 in 值1 值2 值3....

　　　　　　程序

　　　　done

例如:下列脚本会分别打印4次分别是morning noon afternoon evening的值

1 #!/bin/bash
2 #打印时间
3 #Author Mrfeng
4 
5 for time in morning noon afternoon evening
6         do
7                 echo $time
8         done

例如批量解压缩:

 1 #!/bin/bash
 2 #批量解压缩脚本
 3 #Author: Mrf
 4 
 5 path=/opt/lamp
 6 
 7 cd $path
 8 
 9 ls *.tar.gz > ls.log
10 ls *.tgz >> ls.log
11 for i in $(cat ls.log)
12         do
13                 tar zxvf $i &>>cc.log
14         done
15 rm -rf ls.log

2.for 语法二

格式:

1 for ((初始值;循环控制条件;变量变化))
2     do
3            程序
4     done

例如:

1 #!/bin/bash
2 #从1加到100
3 
4 s=0
5 for(( i=1;i<=100;i=i+1 ))
6     do
7         s=$(($s+$i))
8     done
9 echo "the sum of 1+2+...+100is: $s"

例如：批量添加用户

 1 #!/bin/bash
 2 # 批量添加用户数量的用户
 3 # Author:Mr f (E-mail:22222222)
 4 
 5 read -p "Please input user name:" -t 30 name
 6 read -p "Please input the number of users:" -t 30 num
 7 read -p "Please input the password of users:" -t 30 pass
 8 if [ ! -z "$name" -a ! -z "$num" -a ! -z "$pass" ]
 9         then
10                 y=$(echo $num | sed 's/[0-9]//g')
11                 if [ -z "$y" ] ; then
12                         for ((i=1;i<=$num;i=i+1))
13                                 do
14                                         /usr/sbin/useradd $name$i &>/dev/null
15                                         echo $pass | /usr/bin/passwd --stdin $n
16 ame$i &>/dev/null
17                                 done
18                 fi
19 fi
20 cat /etc/passwd | grep user[1-$num] | cut -d ":" -f 1 >>userlist.log

当然我也写了一个利用 userlist.log进行批量删除的脚本方便大家做完实验后清理

1 #!/bin/bash
2 for i in $(cat ./userlist.log)
3         do
4                 /usr/sbin/userdel -r $i &>>del.log
5         done
6 #cat del.log
7 rm -rf del.log