for loop in linux

1. 数字性循环

#!/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  

2.字符性循环

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

for i in `ls`;  
do   
echo $i is file name\! ;  
done   

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