GPaste, a native GNOME Shell clipboard manager, is now available for Ubuntu 12.10 / GNOME Shell 3.6 through the WebUpd8 GNOME 3 PPA.
GPaste features uris support (remembers copied files, not just text), a command line tool, option to backup / restore clipboard history, image support and other useful options.
Install GPaste in Ubuntu 12.10
To install GPaste in Ubuntu 12.10 (with GNOME Shell 3.6), use the following commands:
sudo add-apt-repository ppa:webupd8team/gnome3 sudo apt-get update sudo apt-get install gnome-shell-extensions-gpaste
Once installed, enable the extension using GNOME Tweak Tool.
Note: there's a memory leak when enabling the image support (it occurs when taking a screenshot for instance). For this reason, I've disabled it by default in GPaste package available in our PPA but you can enable it from the GPaste settings if you want to use it anyway.
Unfortunately, the latest GPaste 2.9 doesn't compile successfully for Ubuntu 12.04, that's why the latest version is only available for Ubuntu 12.10.