USAGE
You use rsync in the same way you use rcp. You must specify a source and a destination, one of which may be remote.
Perhaps the best way to explain the syntax is some examples:
rsync *.c foo:src/
this would transfer all files matching the pattern *.c from the current directory to the directory src on the machine foo. If any of the files already exist on the remote system then the rsync remote-update protocol is used to update the file by sending only the differences. See the tech report for details.
rsync -avz foo:src/bar /data/tmp
this would recursively transfer all files from the directory src/bar on the machine foo into the /data/tmp/bar directory on the local machine. The files are transferred in “archive” mode, which ensures that symbolic links, devices, attributes, permissions, ownerships etc are preserved in the transfer. Additionally, compression will be used to reduce the size of data portions of the transfer.
rsync -avz foo:src/bar/ /data/tmp
a trailing slash on the source changes this behavior to transfer all files from the directory src/bar on the machine foo into the /data/tmp/. A trailing / on a source name means “copy the contents of this directory”. Without a trailing slash it means “copy the directory”. This difference becomes particularly important when using the—delete option.
You can also use rsync in local-only mode, where both the source and destination don’t have a ’:’ in the name. In this case it behaves like an improved copy command.
rsync somehost.mydomain.com::
this would list all the anonymous rsync modules available on the host somehost.mydomain.com. (See the following section for more details.)
as found here
If you keep reading on down from there usage on the link
What distro are you building it on?