It is possible to share a printer on a network. For example: two computers sharing one printer while the computers are connected to a home network (local Area Network - LAN). To share files between two computers, mark a folder or drive as shared - search Google on sharing files for more info.
If computers are not connected to the internet at the same time over another cable or wireless, no it is not possible to see the data being transferred
Transferring files
You can transfer files between a tablet and a computer with Bluetooth.
Yes. In most cases you only need a USB cable to transfer files between computers.
FTP
iso files for mac computers
"File-sharing" is a platform-independent concept, that of sharing files between computers. If you are referring to the service / file system that allows other computers on the same network to access files on the local computer, this is usually done with NFS (Network File System). For compatibility with Windows, it is also possible to use Samba.
The purpose of NAS drives on computers is to act as a file server. It allows an individual or business to share files between a number of computers on that shared network.
Obtain the IP addresses of the computers you would like to transfer data to, then use the network to transfer the data.
They are called just that - "files".
You would need a program like DropBox. You would need to have a network connection between the two computers you want to use. Another program would be YouSendIt.