shell脚本之for循环

　　在shell脚本中，for循环有很多种，今天就对以下几种做一个简单的总结。

1、循环数字

#!/bin/bash
for((i=1;i<=10;i++));
do 
    echo $(expr $i \* 3 + 1);
done

#!/bin/bash
for i in $(seq 1 10)
do 
    echo $(expr $i \* 3 + 1);
done

#!/bin/bash
for i in {1..10}
do
    echo $(expr $i \* 3 + 1);
done

#!/bin/bash
 awk 'BEGIN{for(i=1; i<=10; i++) print i}'

　　结果：

4　　7　　10　　13　　16　　19　　22　　25　　28　　31

2、循环字符串

#!/bin/bash
for i in `ls`;
do 
    echo $i is file name\! ;
done

　　结果(输出当前文件名)：

for.sh

#!/bin/bash
for i in $* ;
do
   echo $i is input chart\! ;
done

　　结果（输出当前所有入参）：

192:shell-home xxx$ sh for.sh param1 param2 param3
param1 is input chart!
param2 is input chart!
param3 is input chart!

#!/bin/bash
for i in f1 f2 f3 ;
do
    echo $i is appoint ;
done

　　结果（循环空格隔开的字符list）：

192:shell-home xxx$ sh for.sh 
f1 is appoint
f2 is appoint
f3 is appoint

#!/bin/bash
list="rootfs usr data data2"
for i in $list;
do
    echo $i is appoint ;
done

　　结果（循环list）：

192:shell-home xxx$ sh for.sh 
rootfs is appoint
usr is appoint
data is appoint
data2 is appoint

3、路径查找

#!/bin/bash 
for file in /Volumes/work/*;
do
    echo $file is file path \! ;
done

　　结果（循环查找当前目录）：

192:shell-home xxx$ sh for.sh 
/Volumes/work/BAK_0_MEDIA is file path !
/Volumes/work/BAK_0_TEXT is file path !
/Volumes/work/apache-maven-3.5.3 is file path !
/Volumes/work/apache-tomcat-9.0.8 is file path !
/Volumes/work/chromedriver is file path !
/Volumes/work/git-repository is file path !
/Volumes/work/intellij-setting-files is file path !
/Volumes/work/justfortest is file path !
/Volumes/work/mavenRepository is file path !
/Volumes/work/pathfordownload is file path !
/Volumes/work/selenium-server-standalone-3.0.0.jar is file path !
/Volumes/work/shell-home is file path !

#!/bin/bash
for file in $(ls /Volumes/work)
do
    echo $file is file path \! ;
done

　　结果（循环取出ls的结果）：

192:shell-home xxx$ sh for.sh 
BAK_0_MEDIA is file path !
BAK_0_TEXT is file path !
apache-maven-3.5.3 is file path !
apache-tomcat-9.0.8 is file path !
chromedriver is file path !
git-repository is file path !
intellij-setting-files is file path !
justfortest is file path !
mavenRepository is file path !
pathfordownload is file path !
selenium-server-standalone-3.0.0.jar is file path !
shell-home is file path !