Commonly used for loop writing

Reprinted from: http://blog.csdn.net/BabyFish13/article/details/52981110

Category 1: Numerical Cycles

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}'  

The second category: character loops

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  

Category 3: Pathfinding

for3-1.sh

#!/bin/bash  

for file in /home/username/*;  
do  
echo $file is file path \! ;  
done  

---

for3-2.sh

#!/bin/bash  

for file in $(ls *.sh)  
do  
echo $file is file path \! ;  
done