How to copy files between computers on an ethernet switch?

[Josef Lowder]

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Is there an efficient way to copy files between two computers 
on the same ethernet switch?  I would like to know what is the 
most efficient way to copy files from one computers to another, 
especially if there is a good way to do this when two computers 
are on the same ethernet switch. 

I have been copying files to a flash stick and then physically
moving the flash stick from one computer to another. 

And, I have ftp uploaded (copied) some files from one of my
computers to my web space, and then downloaded the same files 
to another computer. 

But it seems like there must be some more efficient way to 
just send (ftp?) files from one computer to another on my 
locate ethernet network. 

Or, could I connect two computers together via their usb ports 
and transfer files that way?