When I drag a file from one file manager window to another, the file is moved from the source folder to the destination folder. If I keep the control key pressed, the file will be copied. If I hold down the Shift key, the file will also be moved. If you hold down the Alt key, the window moves instead, so I ignore this case.
I'd like to change this behavior to run a script of my choice that retrieves the source path / file and the destination path if the Shift key is held down when the file is dropped. Alternatively, it would work if I could copy the path on the source page from the menu or with the keyboard shortcut (for example, Ctrl + C) and then have a menu option / keyboard shortcut that performs the action in the destination window.
My main use (but not only) will be doing things like creating hard / soft links.
I use PCManFM under LUbuntu 18.04, but if another file manager is the only way, that's okay too.