Shell中for循环的几个常用写法

最近正在学习shell, 关于for循环的写法，发现一篇文章，总结的很全面，再次做个备份。
特殊说明，本文转载来自： Shell中for循环的几个常用写法

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);

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