Change GTK+ theme from command line
First, you need to know that installing a gtk theme from command line is fairly easy. All you have to do is to extract the contents of your theme tar file in /usr/share/themes.
tar -zxf your-theme-.tar.gz /usr/share/themes/
So, to switch your theme, you can install a tool called gtk-theme-switch. It is easy to guess 
.
sudo apt-get install gtk-theme-switch
Then all you have to do is to use this tool and provide it with the path to your theme. For example:
gtk-theme-switch2 /usr/share/themes/GlassyBleu
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