Are you in a command line prompt and you need the full path of the file as an argument? You don’t need to type all of the path manually, not even pre-complete it using TABs. Just navigate to the file.
Here comes the trick part : hold SHIFT while right-clicking it. The context menu will look like so :

I wrote before about the SHIFT-right click so this is somehow connected.

You will then have the full path of the file in the clipboard ready to be pasted wherever you need.

Hope this helps someone! 🙂