Question

编写Linux 的 shell语言 要求设计一个计算器，输入2个数可以计算 +

Answer 1

printf "Please input the first number:"
read number1
printf "Please input the second number:"
read number2
echo "result = $[$number1+$number2]"
这样写比较好看点，输入第一个数 之后 回车 会提示你输入第二个数，再回车就输出结果了！

Answer 2

#!/bin/bash
echo "frist"
read frist
echo "second"
read second
echo "add"
expr $frist + $second

Answer 3

#!/bin/bash

one=${1:-}
two=${2:-}
echo $(($one+$two))

Answer 4

#!/bin/bash
printf "Please input two numbers:"
read numb1 numb2
echo $[$numb1+$numb2]