As of version 17.10, Ubuntu has moved away from the Unity desktop and back to an updated version of the GNOME desktop.
If you upgraded to Ubuntu 17.10 (or even upgraded to Ubuntu 18.04), the Unity desktop is still available, so you can switch back to it (via the gear icon on the login screen), or remove the Unity desktop from Ubuntu. If you do this, you can install new GNOME themes for a whole new look. Here’s how.
The Differences: Icon vs. GTK vs. GNOME Shell Themes
Ubuntu features icon, GTK, and GNOME Shell themes, as well as different ways to install, change, and fix themes when you can’t change the GNOME Shell theme. But what’s the difference?
The following image shows the default look of the GNOME shell in Ubuntu 18.04 and shows the different types of themes you can apply.
Previously, on the Ubuntu Unity desktop, applying an icon theme, or pack, changed the icons for everything, including folder icons in Nautilus and the status icons in the upper-right corner of the screen.
Now, on the new GNOME desktop, icon themes only change the look of icons for installed apps. Make sure the icon theme you want to use has support for a wide range of apps. If you have some applications installed that are not supported by the icon theme you use, the icons for those applications won’t change when you apply the icon theme and you’ll end up with an inconsistent look for your icons.
GTK is a framework for building the graphical user interface (GUI) you see in applications. It’s not the only framework available, but many applications use it. Installing a GTK theme changes how your installed applications look. Later versions of Ubuntu, like 17.10 and 18.04, use GTK3 so you should download GTK3 themes.
GNOME Shell Themes
GNOME Shell themes change the look of the desktop elements like the top panel, activity overview, desktop notifications, and application launcher.
Where to Find GNOME Themes
So, where do you find GNOME themes to download? Here are a few sites that provide a wide range of themes.
Some themes provide all three types of theme elements, so you get a uniform look to your system. Others provide separate icon, GTK, and GNOME Shell themes allowing you to mix and match to get just the look you want.
How to Install Themes in Ubuntu
When browsing for themes, you’ll notice they’re available in different formats. Here are three common ways to install themes.
1. Use PPA Repositories to Install Themes
Some themes are not downloadable. Instead, you run some commands in a Terminal window to add the repository containing the theme and to install the chosen theme.
For example, if you want to make Ubuntu look like System76’s Pop!_OS Linux distribution, run the following three commands, one at a time.
sudo add-apt-repository ppa:system76/pop sudo apt-get update sudo apt-get install pop-theme
The first command installs the repository containing the theme. The second command makes sure the repository is up to date. Then, the third command installs the Pop theme.
The themes available on Noob Labs are installed in this manner. Some of the themes use different commands than the ones we listed here, but each theme includes instructions on how to install it.
Some PPA repositories include multiple themes. If you find a theme you want in a repository you already installed, you don’t need to add the repository again. Just make sure it’s updated using the sudo apt-get update command and then install the theme using the third command above, changing “pop-theme” to the name of the theme you want to install.
2. Use DEB Packages to Install Themes
Some themes come in convenient DEB files. These are executable package files, like EXE files on Windows, that make it easy to install themes (and applications). For example, the Moka icon theme can be installed using a PPA repository or a DEB file.
Download the DEB file and double-click it in Nautilus.
Click Install. Then, enter your password when the Authenticate Required dialog box displays and click Authenticate.
3. Use Archive Files to Install Themes
If you’ve downloaded a theme in a ZIP or TAR file, like the themes found on Ubuntu Themes and some found on GNOME-Look, you’ll have to extract the theme files and manually put them in a specific folder. Don’t worry. It’s not complicated. It’s actually very easy.
For example, we downloaded the Android P theme from GNOME-Look, which comes in a ZIP format.
Before you install the theme files, check to see if you have the hidden folders needed to manually install themes in Ubuntu.
Open Nautilus and go to your Home folder. Press Ctrl + H to show hidden files and folders, which start with a period (.). If you see a the .themes (for GTK and GNOME Shell themes) and .icons (for icon themes) folders, you’re good. If not, you’ll need to create them.
To create the hidden folders, hit Ctrl + Alt + T to open a Terminal window. Run the following commands at the prompt, one at a time.
mkdir ~/.themes mkdir ~/.icons
To extract the theme files, open Nautilus and right-click on the ZIP or TAR file. Select Extract Here.
Copy the extracted folder, go to the .themes folder in your Home folder, and paste the extracted folder there.
How to Change Themes in Ubuntu
Once you’ve installed the themes you want, you need to install the GNOME Tweak Tool (now called Tweaks) to change themes.
Hit Ctrl + Alt + T to open a Terminal window. Type the following command at the prompt, and press Enter.
sudo apt install gnome-tweak-tool
To run Tweaks, click the Show Applications icon in the lower-left corner of your screen.
Type “tweaks” in the search box. Then, click the Tweaks icon.
On the Appearance screen, in the Themes section, you can change the Applications, Cursor, and Icons themes. But you may not be able to change the Shell theme.
If you see a triangle icon with an exclamation point (!) next to the Shell dropdown list, read the next section to find out how to fix this.
How to Enable Changing the GNOME Shell Theme
The ability to change the Shell theme depends on a GNOME Shell extension called User themes. Shell extensions add functionality to or change existing functionality in the GNOME desktop.
To install the User themes extensions, first make sure Tweaks is closed. Then, hit Ctrl + Alt + T to open a Terminal window. And type the following command and press Enter.
sudo apt install gnome-shell-extensions
Restart the GNOME Shell by pressing Alt + F2, typing “r”, and pressing Enter.
Open Tweaks again and go the Extensions screen. Click the ON/OFF slider button to turn on the User themes extension.
Close Tweaks and reopen it. Then, go to the Appearance screen.
You should be able to select a theme from the Shell dropdown list now.
You can use the same theme for all parts of the desktop environment, if the theme covers all the parts. Or you can mix and match themes to get the look you want.
Personalize Your Ubuntu With Themes
You might not like the default look of the new GNOME Shell, but now you can change the look to suit your tastes. For example, you could make your Ubuntu Linux look like Windows.