In bash command & means - run as paralel process and coninue to execute.

For example when you in terminal and you want to run gedit and continue to work in the terminal you run:
$ gedit file.txt &
The process runs in background - actually you can continue to work with terminal and edit file in gedit.

There..... I think you can also not use &... I think you can even just puts symlink to gnome-settings-deamon in this catalog...
When you use & the script will execute and exit...

Is there specific reason to put & or not... That what I did and it worked

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