synchronizing cross platform

If you've been in the computer field at all for the past few years, you've heard of the cloud, amazon s3, ec2, dropbox, windows live, carbonite, google docs, etc....

What if you don't want to store everything in the cloud, either it's too private, or don't want to run afoul of some data privacy laws (hippa?), or it would just cost too much to store all of the hours of baby videos you took.

Now you could use robocopy, or rsync, but these are both one direction.  If you have a laptop that you edit information on along with a desktop (or another laptop?), you probably want to sync your information between the two not just do a one direction backup.

Unison is the program I've been using to keep various repositories of information in sync.   It's cross platform, bi-directional, and doesn't involve the cloud, you control where everything is.

my usage is:
unison -batch profile.prf

the -batch option automates the synchronization process, without it, unison will ask about each and every file that it's copying, should it copy, delete, overwrite one, etc..., so you should probably run it just the first time without the -batch option (if at all).

profile.prf is the name of the configuration file (in the .unison folder if you don't specify a path to it), it can be any name though (pro.prf, home-sync.prf, etc...).

it'll also run over ssh like rsync does, or run a server also like rsync.

a unique feature of unison which I enable is for it to store previous versions of files into a separate folder (or you can store them in a hidden folder in the listing of folders being synchronized).

one of my .prf files, this is for windows, but unison on linux works just as well, just change the folders.

#######------start of prf file--------------

root = //server1/share/synced-folder1
root = //server2/share/synced-folder2

path = subfolder1
path = subfolder2
path = subfolder3

#as this is for windows, don't use fastcheck for unix usually
fastcheck = true
backup = Name *
#ignore any hidden folders, and cd images
ignore = Name {,.}*{.iso}
#where unison stores it's previous versions
backupdir = c:\Users\user1\unison-bak
#where to store the logs
logfile = c:\Users\user1\unison-logs\info-db
#the maximum number of previous versions
maxbackups = 10
#######------end of prf file--------------