语法错误:操作数预期(错误标记为"+")

Question

我正在用bash编写脚本,我收到此错误:

./P4.1: line 10: +: syntax error: operand expected (error token is "+")

这是我的代码:

#!/bin/bash
read string
echo $string >| temp
num1= cut -d" " -f1 temp
num2= cut -d" " -f2 temp
num3= cut -d" " -f3 temp
while [ $num1 -gt $num3 ]
do
        echo $num1
        num1=$[$num1+$num2]
done

怎么了,怎么解决？谢谢.

Answer 1

ceving和Tomek的组合:

#!/bin/bash
read num1 num2 num3
while [ $num1 -lt $num3 ]
do
    echo $num1
    num1=$((num1+num2))
done

Answer 2

使用圆括号进行数值计算：

num1=$((num1 + num2))