Shell 减法

1. 数字相减

• subtraction.sh

#!/usr/bin/env bash
printf "Enter the First Number: "
read -r a
printf "Enter the Second Number: "
read -r b
echo "$a - $b = $((a - b))"

执行：

$ bash subtraction.sh
Enter the First Number: 3
Enter the Second Number: 4
3 - 4 = -1

$ bash subtraction.sh
Enter the First Number: 5
Enter the Second Number: 3
5 - 3 = 2