# **一、变量的赋值方法** 1. **定义法** a=1 2. **传参法** * cat test7.sh ``` #!/bin/bash a=$1 b=$2 echo "a-b=$(($a-$b))" echo "a+b=$(($a+$b))" echo "a*b=$(($a*$b))" echo "a/b=$(($a/$b))" echo "a**b=$(($a**$b))" echo "a%b=$(($a%$b))" ``` 3. **read读入** -p 提示 -t 等待用户输入的时间 `read -t 30 -p "请输入一个数字:" a ` > 请输入一个数字:11 # **二、read企业案例** 判断输入的内容,并根据输入的序号进行相应的操作,脚本如下 * cat select1.sh ``` #!/bin/bash cat <<EOF 1.install lamp 2.install lnmp 3.exit EOF read -p "请选择一个序号（必须是数字）：" num #1.判断是否为整数 expr 2 + $num &>/dev/null if [ $? -ne 0 ] then echo "Usage:$0 {1|2|3}" exit 1 fi #2.判断执行处理 if [ $num -eq 1 ] then echo "install lamp..." elif [ $num -eq 2 ] then echo "install lnmp..." elif [ $num -eq 3 ] then echo "bye." exit else echo "Usage:$0 {1|2|3}" exit 1 fi ```