Read from Sd card and Write to file.TXT

HOW can i read form sd card on ethernet shield and write to file.txt instead of writing to Serial or HTML ?
thank you

Where is file.txt going to be located?

on my PC

HOW can i read form sd card on ethernet shield and write to file.txt instead of writing to Serial

You can't. The only way for the Arduino to talk to your PC is via the serial port, which requires some other application on the PC to be connected to the other end.

If the file content is text (it's kind of implied in your question) and if the Arduino is connected to a Windows PC then you can print it to the serial port and use Gobetwino to log your text to a file on the PC without having to write the PC side code yourself.

thank you very much,i'm reading about it.