[plug] [OT] File Sync for Client

[Tim White]

One of my clients is currently trying to use offline folders (Windows) 
to sync files between his Workstation and Laptop. He also from time to 
time uses a thumbdrive to work on the files at other locations.
Is there some GNU utility that he can use on Windows and Linux computers 
to do 2 way sync of his files. It is over Network and removable media. 
If it is a nice little executable that can be run off the thumbdrive 
then all the better as we can't install some service. It is also on 
different networks so can't have a central server.
Thanks
Tim