Many Linux distributions come with pre-installed icons and themes. Extracting those themes and porting them to another computer is very simple. This method also helps you to backup your themes for future use.
Gnome stores themes in the Root directory. You can access these files by double-clicking on the computer icon on your desktop and selecting “File System” or by opening your Home folder and selecting “File System” from the list on the left-hand sidebar. Then navigate through the folders. Themes are located in usr > share > icons (and usr > share > themes):
Each folder in these directories contains one of your installed themes, icon sets, or mouse pointers (cursors).
Many Linux distros allow users to right-click on a folder and select “Compress…”
If not, you can use your favorite Zip program by simply dragging and dropping the desired folder into the Zip program’s window.
Compress the folder into a single file using the file extension .tar.gz. Select a different location where the file will appear after being created. Do not use the same directory. Place the new file on your desktop or somewhere in your Home folder.
Once you create the new file, you can back it up and move it to another computer.
To install this theme on a different computer, simply move the file to another computer. Right-click on the desktop and select “Change Desktop Background” and click on the Theme tab. Click on the “install…” button:
Navigate to the location of the theme file, select the file and click “Open” to install.
That’s all there is to it! Your theme will now be accessible under the Themes tab and by using the “Customize” button. Repeat the process to install as many themes as you want.
This method also works with many Gnome fork projects, including MATE and Cinnamon.