[BASH]求和

#!/bin/bash
#用while loop计算1到100的和
num=1
sum=0
while [ $num -lt 101 ]; do
    sum=$(($sum+$num))
    num=$(($num+1))
done
printf "sum is %s
" $sum

#!/bin/bash
#用while loop计算1到100之间的偶数和
num=1
sum=0
while [ $num -lt 101 ]; do
    if [ $(($num % 2)) -eq 0 ]; then
       sum=$(($sum+$num))
    fi
    num=$(($num+1))
done
printf "sum is %s
" $sum

#!/bin/bash
#用while loop计算1到100之间的奇数和
num=1
sum=0
while [ $num -lt 101 ]; do
    if [ $(($num % 2)) -ne 0 ]; then #将求偶数的-eq改为-ne即可
       sum=$(($sum+$num))
    fi
    num=$(($num+1))
done
printf "sum is %s
" $sum