Auto-respond only if file exists

Hi,

A user has the following Exim filter:

# Exim filter
if personal alias [email protected]
then
   unseen mail
     subject "Automatic reply: $h_subject:"
     from "[email protected]"
     extra_headers "Content-Type: text/plain; charset=UTF-8"
     file ./.reply.msg
     once ./.reply
     once_repeat 7d
endif

I'd like this "mail" command to run only when the .reply.msg file exists, but wasn't able to figure out from the docs how to impose that condition.

(Without that condition, bounces are generated for the auto-response.)

I suspect that I could mimic the effect by writing "unseen noerror mail", but I'd prefer to avoid the response attempt in the first place if the file doesn't exist.

Thanks,
Peter

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