Install Emerald Window Decorator on Ubuntu and Its Derivatives

Emerald Window Decorator development may have stopped and the package is no longer available in the Ubuntu repositories for a few releases, but there are users who want to continue using it, so to make it easier to install.
Also, please keep in mind that Emerald Window Decorator is no longer developed / supported and while I've tested it for about two days in Ubuntu 13.04 (as well as some brief testing under Ubuntu 12.10 and 12.04 in VirtualBox) and I didn't encounter any issues, there might be bugs or it may not work at all.

Emerald is available in the main WebUpd8 PPA, which is a general PPA with some other packages as well. If you don't like that, you can compile Emerald from source or add the PPA, install Emerald, then remove the PPA.

HalfTime Emerald theme

Divergence IV "A New Hope" Emerald theme

Radial Emerald theme

LittleGlass Emerald theme

Dark glass with Ambiance buttons Emerald theme

Ordinary Emerald theme

Let's start installation, Open Up a terminal and type the follwing commands one by one:

sudo add-apt-repository ppa:nilarimogard/webupd8
sudo apt-get update
sudo apt-get install emerald

Now You have installed emerald!!!

You can get some Emerald themes via Gnome Look, DeviantArt and so on and install them using Emerald Theme Manager: either select "Import" and browse for the .emerald file or simply double click an .emerald theme file and Emerald Theme Manager should install the theme. There are no Emerald themes installed by default so make sure you've installed at least one before proceeding with the next step.

Start Emerald (this will replace your current window decorations) by pressing ALT + F2 and entering: "emerald --replace" (without the quotes). 

To continue using Emerald after a logout / restart, install CompizConfig Settings Manager:

Open Upa Terminal and install it:

sudo apt-get install compizconfig-settings-manager

Now open it from System tools in your menu or by typing "ccsm" (without the quotes) in terminal

click the "Window Decoration" plugin and under "Command", enter: "emerald" (without the quotes):

That's it!

Reverting the changes

If you want to go back to the default window decorator, open CompizConfig Settings Manager, click the "Window Decoration" plugin again and next to "Command", click the reset button on the right:

Then log out and log back in. You can also remove Emerald if you want, but make sure you don't remove it before you reset the CCSM Window Decoration command as explained above: