On 2013-07-20, Mike Cardwell <exim-users@???> wrote: >
> I want a transport_filter to execute under certain conditions only. I
> attempted making it so that if the condition didn't succeed then it
> expanded to an empty string, but that didn't work. E.g:
>
> transport_filter = "${if CONDITION{command to filter though}{}}"
expand it to "cat" if you want a filter that makes no changes.
