read -p "请输入一个成绩：" sorce
if [ "$sorce" -ge 90 -a "$sorce" -le 100 ]
then
	echo 'A'
elif [ "$sorce" -ge 80 -a "$sorce" -lt 90 ]
then
	echo 'B'
elif [ "$sorce" -ge 70 -a "$sorce" -lt 80 ]
then
	echo 'C'
elif [ "$sorce" -ge 60 -a "$sorce" -lt 70 ]
then
	echo 'D'
else 
	echo "不及格"
fi

read -p "请输入你要操作的文件" filename
if [ -e "$filename" ]
then
	echo "文件存在"
	if [ -f "$filename" ]
	then
		echo "文件为普通文件"
	else
		echo "文件格式不匹配"
	fi
else
	echo "文件不存在正在为你创建文件"
	touch $filename
fi
echo "hello world">>$filename
echo "已完成"