假设有文件test.txt,内容如下:1, linux idc, Title 639, Price $9.302, linuxidc ninhao, Title 761, Price $5.903, linuxmi nihao, Title 880, Price $9.304, linuxmi com, Title 198, Price $1.305, Johnny Cash, Title 582, Price $6.506, Elvis Presley, Title 370, Price $9.307, John Lennon, Title 571, Price $8.908, Michael Jackson, Title 673, Price $7.509, linuxidc com, Title 585, Price $1.80请将文件中所有价格为9.30的价格改为8.88。