1、vim even.sh

#!/bin/bash

SUM=0

I=0

while [ $I -le 100 ];do

if [ `expr $I % 2 ` -eq 0 ];then

let SUM+=$I

fi

let I++

done

echo "The even sum is $SUM"

2.、vim even.sh

#!/bin/bash

I=0

SUM=0

until [ $I -gt 100 ];do

if [ $(($I % 2)) -eq 0 ];then

let SUM+=$I

fi

let I++

done

echo "The even sum is $SUM"