shell腳本之for循環

　　在shell腳本中，for循環有很多種，今天就對以下幾種做一個簡單的總結。

1、循環數字

#!/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}'

　　結果：

4　　7　　10　　13　　16　　19　　22　　25　　28　　31

2、循環字符串

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

　　結果(輸出當前文件名)：

for.sh

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

　　結果（輸出當前所有入參）：

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

　　結果（循環空格隔開的字符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

　　結果（循環list）：

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

3、路徑查找

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

　　結果（循環查找當前目錄）：

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

　　結果（循環取出ls的結果）：

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 !