variables

#!/bin/bash

#variables.sh

fruit=apple

count=5

echo "We have $count ${fruit}(s)"

let：直接执行

let re=2

echo $re

let n++/--

re=$(expr $n + 5)      以上只用于整数，不支持浮点

bc：浮点

echo "scale=2;3/8" |bc  小数位2