Opening a link in Firefox from Terminal is pretty straightforward and there are many options available to the firefox command. E.g you can do firefox -new-window "http://stackoverflow.com" to open the link in a new window.
I wonder if you can do the same with Safari on a Mac? open "http://stackoverflow.com" just opens a new Tab if there's already a window of Safari opened.
I know of apps that let you switch between "Open in new tab" and "Open in new window". Is there a special prefix to the URL to tell Safari to open a new window? Or is it just possible through Objective-C code?