用shell实现根据输入分数判断等级

#!/bin/bash
#filename:ak    
echo -n "enter your grades:"   
read grade
if [ $grade -ge 0 -a $grade -le 59 ];then   
    echo "fail"
elif [ $grade -ge 60 -a $grade -le 100 ];then
    echo "pass" 
else
    echo "error" 
fi

运行结果：

用if语句ABCDE分级：

#!/bin/bash
#filename:zuoye    
echo -n "enter your grades:"   
read grade
if [ $grade -ge 0 -a $grade -le 59 ];then   
    echo "E"
elif [ $grade -ge 60 -a $grade -le 69 ];then
    echo "D" 
elif [ $grade -ge 70 -a $grade -le 79 ];then
    echo "C" 
elif [ $grade -ge 80 -a $grade -le 89 ];then
    echo "B" 
elif [ $grade -ge 90 -a $grade -le 100 ];then
    echo "A" 
else
    echo "error" 
fi

运行结果：

用case语句分级

#!/bin/bash
#filename:case
echo -n "enter your grades:"
read grade
case $grade in
    9[0-9]|100) echo A;;
    8[0-9]) echo B;;
    7[0-9]) echo C;;
    6[0-9]) echo D;;
    [0-5][0-9]|[0-9]) echo E;;
    *) echo ERROR;;
esac

运行结果：