Above is a conversation about cables, if the computers have gigabit nics, or were made in the last 10 years then there is a high chance you can just connect them direct with a cable.
After connecting cable, assign each NIC manually an ip in the same subnet. e.g.
192.168.10.1/24 and
192.168.10.2/24
Then, if you are using windows you can use Windows built-in file sharing;
if you are using linux or bsd you can use rsync.
You can use rsync in windows too but i dont want to explain that.