How to include the date in backup file

I've just tried

Prefs BACKUP=all to "L:\Web\Opus"

But there is no example, how to include the current date in the built in help file (F1).

You can use {date} and {time} in commands to insert them into names and other things.

Yes, but exactly how?

Prefs BACKUP {date}=all to “L:\Web\Opus” or
Prefs BACKUP=all {date} to “L:\Web\Opus”

doesn't work. I can't figure out, where to place it.

This should work:

Prefs BACKUP=all TO "L:\Web\Opus\DOpus_Backup {date|yyyy-MM-dd}"

Thanks, that did it!