Redirect real webcam to a virtual webcam via terminal

Is there a way to redirect a real webcam to a virtual webcam from the command line, for example using the v4l2loopback module with ffmpeg ?

Details

I have an old webcam which works with most software (vlc, cheese, etc.), but not with others (Skype).

A possible workaround to make it work with such software is to redirect it to a virtual webcam using the v4l2loopback module, as done by Webcamoid, but I need to do it from the command line, for example via ffmpeg.

I am sure this is possible via ffmpeg as well, but since real webcams are rarely redirected to virtual ones, I found no examples online (the only examples I have found, like this one, redirect screen captures or existing videos to the virtual webcam instead).