#!/bin/bash
read -p "Please input your score: " score if [ $score -le 100 -a $score -ge 90 ];then echo "A" elif [ $score -lt 90 -a $score -ge 80 ];then echo "B" elif [ $score -lt 80 -a $score -ge 70 ];then echo "C" elif [ $score -lt 70 -a $score -ge 60 ];then echo "D" elif [ $score -lt 60 ];then echo "E" else echo "Error" fi
注释： [ 1 -gt 10 ] 大于 [ 1 -lt 10 ] 小于 [ 1 -eq 10 ] 等于 [ 1 -ne 10 ] 不等于 [ 1 -ge 10 ] 大于等于 [ 1 -le 10 ] 小于等于
