I am on Mac, and tried basically:
vlc --sout '#R5 TV (Chromecast)' --sout-chromecast-ip=192.168.0.8 --demux-filter=demux_chromecast
Vlc opens, but it does not seem to select the renderer to the chrome cast in my menu.
How can I make this choice automatic? I believe most things are possible from Terminal for VLC.
I looked at
vlc --longhelp --advanced
Which is quite long but could not find it.
This
path/to/vlc '/nothing.mp4' --sout '#chromecast' --sout-chromecast-ip=192.168.0.8 --demux-filter=demux_chromecast"
seems to work on MacOS at least. It won't play nothing.mp4 but allows you to start playing anything, like with a VLC remote application from phone.