Share several common writing methods based on the for loop in Shell

#!/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}' 

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

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

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

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

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

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