I use Linux, but rarely its desktop. I mostly just use command line. OwnCloud provides a command line program: owncloudcmd. Here are the steps to set it up and use it.
First install the OwnCloud client. Go to: https://software.opensuse.org/download/package?project=isv:ownCloud:desktop&package=owncloud-client and select Linxu flavor and version. I use Ubuntu 16.04:
sudo sh -c "echo 'deb http://download.opensuse.org/repositories/isv:/ownCloud:/desktop/Ubuntu_16.04/ /' > /etc/apt/sources.list.d/owncloud-client.list"
sudo apt-get update
sudo apt-get install owncloud-client
To do an owncloud sync, you need to know its webdav url. It`s usually:
http://serveraddress/remote.php/webdav/folder_path
If you unsure of the URL. just login to your owncloud web interface, click on Settings at the lower left corner, it will show WebDAV, copy the address, it should end with /remote.php/webdav/.
To sync a specific folder or file, append the path after /webdav/. For example I have top level wiki folder I want to sync, its url is: http://myserver/remote.php/webdav/wiki, on the command line:
owncloudcmd -n ownCloud/wiki http://myserver/remote.php/webdav/wiki
It will prompt for username and password. The program exits when it finish syncing.