写出 shell 脚本中所有循环语法

for 循环 :

for i in $(ls);do

echo item:$i

done

while 循环 :

#!/bin/bash

COUNTER=0

while [ $COUNTER -lt 10 ]; do

echo The counter is $COUNTER

let COUNTER=COUNTER+1

done

until 循环 :

#!/bin/bash

COUNTER=20

until [ $COUNTER -lt 10 ]; do

echo COUNTER $COUNTER

let COUNTER-=1

done