In my project i need to send file to pc from my device for further analysis. It will be saved on a SD card in the device then i have to send it to pc. I need a sketch to do this part. If i send something to pc i don't know... do i have receive it there or it will be automatically received.
Is your last sentence a statement or a question? I think you know by know that nothing happens automatically on a pc unless there is a program controlling that behavior.
You mentioned Ethernet in the title of your post, that and wifi are some of the ways to communicate with a pc. Of course there are other methods (USB, serial,etc) but wired Ethernet and wifi are IMO the easiest when programming an Arduino to send lots of data to a pc.
I would start by reviewing the Ethernet example projects here: https://www.arduino.cc/en/Tutorial/LibraryExamples
The UDP send/receive is the closest to what you want to do. Review the program and then Google for other Arduino & Ethernet programs. After you've absorbed some of that content, return here with your questions for the next step in the process if you're unsure.
I just need to send data from arduino. So, i need to build a one way connection. Suppose i have sent some files to pc using this UDP protocol then what will i have to do to receive it in pc?