Documentation regarding substituting SRC with NUL

[pipur]

Hi.
I'm using this to make Exiftool spit out a file after it's ready after the latest -execute (to let another application know that it's ready):
-textOut+!
%0f<readyFile>
nul
-execute

Using nul let's me escape using a dummy image file.

I'm now documenting this and can't for the life of me locate where I found this work around.

Any pointer would be most welcome.

Kind regards
/p

[Phil Harvey]

I don't understand what you want.

Are you asking about the purpose of -textOut+! %0f ?

- Phil