In order to keep your existing schemes make sure you backup your custom color schemes from the ~/.config/tilix/schemes directory. In some cases if you have a scheme that has the same name with the new scheme this script overwrites it. So, it is your responsibility to take care of your files. Also, this directory is by default, if you use custom take that one into consideration. Now we can run the script. But, the script requires your tilix color-scheme folder. it is ~/.config/tilix/schemes by default. If you use a different directory give that directory to script. Also, make sure that the directory exists.