Well, that depends what you are doing -- I added the command in a field rule, so I could use a field value in my filter. My command looks like this:
concat("FilterOwssvr /dsname=owssvr /filter=LinkTitle /value=",
.)
With that last underlined dot having been selected by clicking "Insert field or group" in the formula editor.
Thanks for your feedback on the documentation, by the way. I'll take a look at it and file a case for review.