shell学习二十五--for循环

桃扇骨 2022-06-04 03:27 505阅读 0赞

一、for循环结构  
1、for循环语法  
for 变量 in 变量取值列表  
do  
    指令  
done  
提示：在此结构中“in 变量取值列表”可以省略，省略时相当于in “$@”，使用for i就相当于使用for i in “$@”。  
2、c语言型for循环语法  
for ((exp1;exp2;exp3))  
do  
    指令  
done  
  
实例1：  
\[root@node01 day12\]\# vi for01\_sh  
\#!/bin/sh  
for i in 5 4 3 2 1  
do  
  echo $i  
done  
\[root@node01 day12\]\# sh for01\_sh   
5  
4  
3  
2  
1  
  
3、使用大括号  
\[root@node01 day12\]\# vi for02.sh   
\#!/bin/sh  
for i in \{5..1\}  
do  
  echo $i  
done  
\[root@node01 day12\]\# sh for02.sh   
5  
4  
3  
2  
  
4、使用seq  
\[root@node01 day12\]\# vi for03.sh   
\#!/bin/sh  
for i in \`seq 5 -1 1\`      -1是步长  
do  
  echo $i  
done  
\[root@node01 day12\]\# sh for03.sh   
5  
4  
3  
2  
1  
  
5、开机自启动实例  
开发脚本仅设置sshd、crond、rsyslog、network自启动，其他关闭。  
\[root@node01 day12\]\# vi auto\_start.sh  
for name in $service  
\#!/bin/sh  
LANG=en  
service=\`chkconfig --list|grep 3:on|awk '\{print $1\}'\`  
for name in $service  
do  
   chkconfig $name off  
done  
  
for name in rsyslog network crond sshd sysstat  
do  
  chkconfig $name on  
done  
\[root@node01 day12\]\# sh auto\_start.sh   
\[root@node01 day12\]\# chkconfig --list|grep 3:on  
crond           0:off   1:off   2:on    3:on    4:on    5:on    6:off  
network         0:off   1:off   2:on    3:on    4:on    5:on    6:off  
rsyslog         0:off   1:off   2:on    3:on    4:on    5:on    6:off  
sshd            0:off   1:off   2:on    3:on    4:on    5:on    6:off  
sysstat         0:off   1:on    2:on    3:on    4:on    5:on    6:off  
  
也可以一步实现  
方法二：  
for wolf  in \`chkconig --list|grep "3:on"|awk '\{print $1\}'|grep -vE "crond|network|sshd|rsyslog|sysstat"\`;do chkconfig $wolf off;done  
chkconfig --list | grep 3:on  
方法三：  
chkconfig --list|grep 3:on|grep -vE "crond|sshd|network|rsyslog|sysstat"|awk '\{print "chkconfig " $1 " off"\}' |bash  
  
1加到100  
\[root@node01 day12\]\# vi for-sum.sh   
\#!/bin/sh  
for((i=0; i<=100; i++))  
do  
   ((j=j+i))  
done  
echo $j  
\[root@node01 day12\]\# sh for-sum.sh   
5050  
  
\[root@node01 day12\]\# vi for\_curl.sh   
\#!/bin/sh  
for((i=0; i<=100; i++))  
do  
   curl http://www.baidu.com  
done  
  
二、四道题  
1、使用for循环在/data/wolf目录下批量创建10个文件，名称依次为：  
wolf-1  
wolf-2  
wolf-3  
。。。  
wolf-10  
例如随机创建10个文件，包含wolf字符串，结尾是1-10，扩展名是html。  
\[root@node01 day12\]\# cat 01.sh   
\#!/bin/sh  
\[ ! -d /data/wolf \] && mkdir -p /data/wolf  
for i in \`seq 10\`  
do  
  touch /data/wolf/wolf-$\{i\}.html  
done  
\[root@node01 data\]\# cd wolf  
\[root@node01 wolf\]\# ls  
wolf-10.html  wolf-1.html  wolf-2.html  wolf-3.html  wolf-4.html  wolf-5.html  wolf-6.html  wolf-7.html  wolf-8.html  wolf-9.html  
2、将以上文件名中的wolf全部改成linux（用for循环实现）,并且扩展名改成大写，for循环的循环体不能出现wolf  
\[root@node01 day12\]\# vi 02.sh        
\#!/bin/sh  
for i in \`seq 10\`  
do  
  cd /data/wolf  
  mv wolf-$\{i\}.html linux$\{i\}.HTML  
done  
\[root@node01 day12\]\# sh 02.sh        
\[root@node01 day12\]\# ll /data/wolf/  
total 0  
\-rw-r--r-- 1 root root 0 Aug  6 11:57 linux10.HTML  
\-rw-r--r-- 1 root root 0 Aug  6 11:57 linux1.HTML  
\-rw-r--r-- 1 root root 0 Aug  6 11:57 linux2.HTML  
\-rw-r--r-- 1 root root 0 Aug  6 11:57 linux3.HTML  
\-rw-r--r-- 1 root root 0 Aug  6 11:57 linux4.HTML  
\-rw-r--r-- 1 root root 0 Aug  6 11:57 linux5.HTML  
\-rw-r--r-- 1 root root 0 Aug  6 11:57 linux6.HTML  
\-rw-r--r-- 1 root root 0 Aug  6 11:57 linux7.HTML  
\-rw-r--r-- 1 root root 0 Aug  6 11:57 linux8.HTML  
\-rw-r--r-- 1 root root 0 Aug  6 11:57 linux9.HTML  
\-rw-r--r-- 1 root root 0 Aug  6 11:56 linux.HTML  
\-rw-r--r-- 1 root root 0 Aug  6 11:56 linux\{i\}.HTML  
  
\[root@node01 ~\]\# cd /data/wolf  
\[root@node01 wolf\]\# ls  
wolf-10.html  wolf-2.html  wolf-4.html  wolf-6.html  wolf-8.html  
wolf-1.html   wolf-3.html  wolf-5.html  wolf-7.html  wolf-9.html  
\[root@node01 wolf\]\# f=wolf-1.html  
\[root@node01 wolf\]\# echo $f  
wolf-1.html  
\[root@node01 wolf\]\# echo $f|sed 's\#wolf\#linux\#g'  
linux-1.html  
上面这个没对，没改扩展名  
方法1、  
\[root@node01 wolf\]\# echo $f|sed 's\#wolf\#linux\#g'  
linux-1.html  
\[root@node01 wolf\]\# echo $f|sed 's\#wolf\#linux\#g'|sed 's\#html\#HTML\#g'  
linux-1.HTML  
\[root@node01 wolf\]\# mv $f \`echo $f |sed 's\#wolf\#linux\#g'|sed 's\#html\#HTML\#g'\`  
\[root@node01 wolf\]\# ll  
total 0  
\-rw-r--r-- 1 root root 0 Aug  6 11:58 linux-1.HTML  
\[root@node01 day12\]\# vi 03.sh  
\#!/bin/sh  
cd /data/wolf  
for f in \`ls \*.html\`  
do  
  mv $f \`echo $f |sed 's\#wolf\#linux\#g'|sed 's\#html\#HTML\#g'\`  
done  
\[root@node01 day12\]\# sh 03.sh  
\[root@node01 wolf\]\# ll  
total 0  
\-rw-r--r-- 1 root root 0 Aug  6 11:58 linux-10.HTML  
\-rw-r--r-- 1 root root 0 Aug  6 11:58 linux-1.HTML  
\-rw-r--r-- 1 root root 0 Aug  6 11:58 linux-2.HTML  
\-rw-r--r-- 1 root root 0 Aug  6 11:58 linux-3.HTML  
\-rw-r--r-- 1 root root 0 Aug  6 11:58 linux-4.HTML  
\-rw-r--r-- 1 root root 0 Aug  6 11:58 linux-5.HTML  
\-rw-r--r-- 1 root root 0 Aug  6 11:58 linux-6.HTML  
\-rw-r--r-- 1 root root 0 Aug  6 11:58 linux-7.HTML  
\-rw-r--r-- 1 root root 0 Aug  6 11:58 linux-8.HTML  
\-rw-r--r-- 1 root root 0 Aug  6 11:58 linux-9.HTM   
方法2  
\#!/bin/sh  
cd /data/wolf  
for f in \`ls \*.html\`  
do  
  \#mv $f \`echo $f|sed 's\#wolf\#linux\#g'|sed 's\#html\#HTML\#g'\`  
  mv $f \`echo $f|sed 's\#wolf\$.\*\$.html\#linux\\1.HTML\#g'\`  
done  
\[root@node01 wolf\]\# ll  
total 0  
\-rw-r--r-- 1 root root 0 Aug  6 13:26 linux-10.HTML  
\-rw-r--r-- 1 root root 0 Aug  6 13:26 linux-1.HTML  
\-rw-r--r-- 1 root root 0 Aug  6 13:26 linux-2.HTML  
\-rw-r--r-- 1 root root 0 Aug  6 13:26 linux-3.HTML  
\-rw-r--r-- 1 root root 0 Aug  6 13:26 linux-4.HTML  
\-rw-r--r-- 1 root root 0 Aug  6 13:26 linux-5.HTML  
\-rw-r--r-- 1 root root 0 Aug  6 13:26 linux-6.HTML  
\-rw-r--r-- 1 root root 0 Aug  6 13:26 linux-7.HTML  
\-rw-r--r-- 1 root root 0 Aug  6 13:26 linux-8.HTML  
\-rw-r--r-- 1 root root 0 Aug  6 13:26 linux-9.HTML  
  
rename可以实现  
3、批量创建10个系统帐号wolf01-wolf10并设置密码（密码不能相同）  
\[root@node01 day12\]\# vi 05.sh  
\#!/bin/sh  
for i in \`seq -w 10\`  
do  
   useradd wolf$i&&\\  
   echo "root$i"|passwd --stdin wolf$i  
done  
\[root@node01 day12\]\# sh 05.sh   
Changing password for user wolf01.  
passwd: all authentication tokens updated successfully.  
Changing password for user wolf02.  
passwd: all authentication tokens updated successfully.  
Changing password for user wolf03.  
passwd: all authentication tokens updated successfully.  
Changing password for user wolf04.  
passwd: all authentication tokens updated successfully.  
Changing password for user wolf05.  
passwd: all authentication tokens updated successfully.  
Changing password for user wolf06.  
passwd: all authentication tokens updated successfully.  
Changing password for user wolf07.  
passwd: all authentication tokens updated successfully.  
Changing password for user wolf08.  
passwd: all authentication tokens updated successfully.  
Changing password for user wolf09.  
passwd: all authentication tokens updated successfully.  
Changing password for user wolf10.  
passwd: all authentication tokens updated successfully.  
\[root@node01 day12\]\# su - wolf01  
welcome to wolf linux  
\[wolf01@node01 ~\]$ id  
uid=502(wolf01) gid=502(wolf01) groups=502(wolf01)  
\[wolf01@node01 ~\]$ su - wolf02  
Password:   
welcome to wolf linux  
\[wolf02@node01 ~\]$   
\[wolf02@node01 ~\]$ whoami  
wolf02  
技术点  
a：00 01 02  03。。。10  
b:无交互设置密码  
也可以这样  
 -p, --password PASSWORD  
           The encrypted password, as returned by crypt(3). The default is to disable the password.  
  
  
           Note: This option is not recommended because the password (or encrypted password) will be visible by users listing the processes.  
  
  
           You should make sure the password respects the system´s password policy.  
\#!/bin/sh  
for i in \`seq -w 10\`  
do  
   userdel -r wolf$i  
   useradd wolf$i&& -p root$i  
\#   echo "root$i"|passwd --stdin wolf$i  
done  
  
4、批量创建10个系统帐号wolf01-wolf10并设置密码（密码随机8位字符串）  
\[root@node01 day12\]\# echo $RANDOM  
16803  
\[root@node01 day12\]\# echo $((RANDOM+100000000))  
100006409  
\[root@node01 day12\]\# echo $RANDOM|md5sum                32位  
8ba9344650cf6474a17359692e5932b0  -  
\[root@node01 day12\]\# echo $RANDOM|md5sum|cut -c 1-8     使用cut取8位  
a6b44f06  
\[root@node01 day12\]\# echo "\`date\`$RANDOM"|md5sum|cut -c 1-8  
1362138d  
\[root@node01 day12\]\# echo "\`date +%s\`$RANDOM"|md5sum|cut -c 1-8  
2a4e0da6  
  
删除脚本  
\[root@node01 day12\]\# vi rm\_user.sh  
\#!/bin/sh  
for i in  \`seq -w 10\`  
do  
   userdel -r wolf$i  
done  
  
随机数用两次的话 需要定义变量  
\[root@node01 day12\]\#  
\#!/bin/sh  
for i in \`seq -w 10\`  
do  
   pass="\`date +%s\`$RANDOM"|md5sum|cut -c 1-8\`  
   useradd wolf$i&&\\  
   echo "$pass"|passwd --stdin wolf$i  
   echo -e "wolf $i\\t $pass" >>/data/wolf/pass.txt  
done  
  
标准方法  
\[root@node01 day12\]\# vi 07.sh   
\#!/bin/sh  
for i in \`seq -w 10\`  
do  
   pass=\`echo "$RANDOM"|md5sum|cut -c 1-8\`  
   useradd wolf$i&&\\  
   echo "$pass"|passwd --stdin wolf$i  
   echo -e "wolf $i\\t $pass" >>/data/wolf/pass.txt  
done  
  
\[root@node01 day12\]\# sh 07.sh                 
Changing password for user wolf01.  
passwd: all authentication tokens updated successfully.  
Changing password for user wolf02.  
passwd: all authentication tokens updated successfully.  
Changing password for user wolf03.  
passwd: all authentication tokens updated successfully.  
Changing password for user wolf04.  
passwd: all authentication tokens updated successfully.  
Changing password for user wolf05.  
passwd: all authentication tokens updated successfully.  
Changing password for user wolf06.  
passwd: all authentication tokens updated successfully.  
Changing password for user wolf07.  
passwd: all authentication tokens updated successfully.  
Changing password for user wolf08.  
passwd: all authentication tokens updated successfully.  
Changing password for user wolf09.  
passwd: all authentication tokens updated successfully.  
Changing password for user wolf10.  
passwd: all authentication tokens updated successfully.   
\[root@node01 day12\]\# cat /data/wolf/pass.txt   
wolf 01  87d5ca7c  
wolf 02  1a394ec2  
wolf 03  d9497158  
wolf 04  b682731c  
wolf 05  0463a374  
wolf 06  24055dba  
wolf 07  30a02856  
wolf 08  1796c864  
wolf 09  0944b988  
wolf 10  a42f8a52  
  
\[root@node01 day12\]\# vi 07.sh   
\#!/bin/sh  
for i in \`seq -w 10\`  
do  
   pass=\`echo "$RANDOM"|md5sum|cut -c 1-8\`  
   useradd wolf$i&&\\  
   echo "$pass"|passwd --stdin wolf$i  
   echo -e "wolf$i\\t $pass" >>/data/wolf/pass.txt  
done  
  
wolf01   e6e49473  
wolf02   8d986dfd  
wolf03   b915f9d9  
wolf04   7e419d06  
wolf05   4c45b423  
wolf06   c79eb81b  
wolf07   7381ad8d  
wolf08   a9caaa8b  
wolf09   a599dd26  
wolf10   e170f057  
  
============================================  
1.for … in 语句  
for 变量 in seq字符串  
do  
     指令  
done  
说明：seq字符串 只要用空格字符分割，每次for…in 读取时候，就会按顺序将读到值，给前面的变量  
  
  
\#!/bin/sh  
for i in $(seq 10); do  
    echo $i;  
done;  
  
2.for((赋值；条件；运算语句))  
for((赋值；条件；运算语句))  
do  
action  
done;  
  
\#!/bin/sh  
for((i=1;i<=10;i++));do  
    echo $i;  
done;  
=================================================  
学习资料  
第一类：数字性循环  
\-----------------------------  
for1-1.sh  
\#!/bin/bash    
    
for((i=1;i<=10;i++));    
do     
echo $(expr $i \\\* 3 + 1);    
done    
  
\-----------------------------  
for1-2.sh  
\#!/bin/bash    
    
for i in $(seq 1 10)    
do     
echo $(expr $i \\\* 3 + 1);    
done    
  
\-----------------------------  
for1-3.sh  
\#!/bin/bash    
    
for i in \{1..10\}    
do    
echo $(expr $i \\\* 3 + 1);    
done    
  
\----------------------------  
for1-4.sh  
\#!/bin/bash    
    
awk 'BEGIN\{for(i=1; i<=10; i++) print i\}'    
  
第二类：字符性循环  
\-----------------------------  
for2-1.sh  
\#!/bin/bash    
    
for i in \`ls\`;    
do     
echo $i is file name\\! ;    
done    
  
\-----------------------------  
for2-2.sh  
\#!/bin/bash    
    
for i in $\* ;    
do    
echo $i is input chart\\! ;    
done    
  
\-----------------------------  
for2-3.sh  
\#!/bin/bash    
    
for i in f1 f2 f3 ;    
do    
echo $i is appoint ;    
done    
  
\-----------------------------  
for2-4.sh  
\#!/bin/bash    
    
list="rootfs usr data data2"    
for i in $list;    
do    
echo $i is appoint ;    
done    
  
第三类：路径查找  
\-----------------------------  
for3-1.sh  
\#!/bin/bash    
    
for file in /proc/\*;    
do    
echo $file is file path \\! ;    
done    
  
\-----------------------------  
for3-2.sh  
\#!/bin/bash    
    
for file in $(ls \*.sh)    
do    
echo $file is file path \\! ;    
done    
\# 三.循环控制语句   
\# break 命令不执行当前循环体内break下面的语句从当前循环退出.   
\# continue 命令是程序在本循体内忽略下面的语句,从循环头开始执行