for循环无参数取值列表的使用

[root@localhost array]# cat for.sh 
#!/bin/bash
for i 
do
    #echo abc
    let sum+=$i
done
    echo $sum
[root@localhost array]# sh for.sh  1 2 3 4 5
15
[root@localhost array]# 

等价与

[root@localhost array]# cat for.sh
#!/bin/bash
for i in $*
do
    #echo abc
    let sum+=$i
done
    echo $sum
[root@localhost array]# sh for.sh  1 2 3 4 5
15
[root@localhost array]#