Rhythmbox-GMusic is a Rhythmbox plugin for Google Play Music.
Using Rhythmbox-GMusic, you can play your Google Play music using Rhythmbox. The plugin features a very simple and uses an interface similar to the default Rhythmbox layout, with two columns for artists and albums followed by a list of tracks. There's also a search bar so you can easily search your Google Play Music.
There's no contect menu so you can't right click tracks to add them to the play queue, but you can do that by using drag and drop.
Also, the plugin doesn't allow you to add tracks to local playlists (except the Queue playlist which I've mentioned above), but it can read playlists created using the Google Play Music web interface.
Please note that for now, Google Play Music All Access is not supported.
Install Rhythmbox Google Music Plugin in Ubuntu
To install Rhythmbox-Gmusic in Ubuntu 13.04, use the following commands:
For Ubuntu 12.10, you need to manually download and install python-validictory from HERE, then run the commands above.
sudo add-apt-repository ppa:nvbn-rm/ppa sudo apt-get update sudo apt-get install rhythmbox-gmusic python-dateutil python-requests python-validictory
Unfortunately the Ubuntu 12.04 package doesn't work properly, at least with the Rhythmbox 2.96 package available in the Ubuntu 12.04 repositories.
Once installed, open Rhythmbox (restart it if it was running), from its menu select Plugins and enable the Google Play Music plugin. You should then have a new "Google Music" entry in the Rhythmbox sidebar - here, enter you Google username and password (the password is stored in the GNOME Keyring) and upon logging in successfully, your Google Play music should show up.
For installing the Rhythmbox Google Music plugin via PIP, grab the source code or report bugs, see its GitHub page.
Also see: Nuvola Player, a cloud music player that supports Google Play Music, Grooveshark, Hype Machine, 8tracks, Pandora, Deezer, Rdio and Amazon Cloud Player