# For KDE > 5.10
kquitapp5 plasmashell || killall plasmashell && kstart5 plasmashell

Remarks:

1. If you are not sure which KDE version your run, kinfocenter –version will tell you.
2. you can skip the kquitapp5 plasmashell || part if you don’t want to be stuck in the timeout when plasmashell is not responding.

Original Source: kwin - Can I restart the KDE Plasma Desktop without logging out? - Ask Ubuntu