Bash:-set设置位置变量结合while和shift使用

#!/bin/bash

aaa=(   )
bbb=(a b c d)

set -- ${aaa[@]}
while (($#>));do
        echo ${}
        shift
done

set --

echo "-----------------------"

set -- ${bbb[@]}
while (($#>));do
        echo ${}
        shift
done
set --

----------(结果)--------------

-----------------------
a
b
c
d