Here's what you do:
Let's say you want to send a folder called ABC from computer X to computer Y. Then, fire up terminal on computer Y first and type the following commands:
hostname -I nc -l 9898 | tar xv
"hostname -I" shows all IP addresses associated with the host Y. You'll need to note these down to be used on computer X. "nc" is a utility that allows for arbitrary TCP and UDP connections and listens. "-l 9898" is a flag for nc to open port 9898 and listen for connections. The "|" pipes the output of nc (i.e. whatever comes from the network) into the next command "tar" which is an archival utility. The "xv" part stands for extract verbose which means that the archive coming from nc is extracted and each file name is printed out as it is extracted.
Once you're done running the above command on Y, run the following command on X:
tar c ABC | nc IP 9898
The "tar c" part stands for "use tar to compress" ABC (the folder to be sent). IP is the IP address got from the "hostname -I" command on computer Y. "nc IP 9898" connects to computer Y on port 9898 and sends the data from the tar command to the other computer.
Since no extra data is transferred in this way, the data should be transferred at the maximum (theoretical) limit of your network. If your network is unstable, this might actually cause a problem since no error correction codes are sent; however, if your network is stable (or all you are sending is movies or the like) then it shouldn't matter much.
Do you know of any other fast ways to transfer data on the network? Leave a comment below. :)