How to prompt user to select node, and store its X,Y,Z locations

Hi,

I am writing a tcl script and I am trying to get the user to inform the script of where the script should be taking place. I want to request this by having the user select (pick) a node.

From this node I would want to retrieve the X,Y,Z locations of that node, and store them in a variable and proceed with the rest of the script.

How might I do this?

Thanks in advance for the help!

Tyler