How to restart only the graphical side of OS X via Terminal

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I have a variety of mac minis that I use to display stats and system status. Sometimes the Safari browser that is displaying the stats graphs on those remote mac minis locks up / runs out of memory. This makes using Remote Desktop to restart the remote Safari session impossible as I can't login to the machine. Rather than walk over to force a reboot I can ssh into the box and restart the WindowsServer (WindowsServer is the graphical user interface manager and is typically the thing that is borked). 

To resolve this issue I ssh into the machine via Terminal and then run the following command:

sudo killall -HUP WindowServer

Any open applications will be forced to close so use the command with caution.