[exim] .forward and pipes.

I have set up my .forward file to look like this...

# exim filter
unseen pipe "/path/to/command"

And when I receive a message, the bash file 'command' is run, as
expected. However, somewhere deep within the bowels of 'command', I
have an error and not everything is completing as expected. I suspect
it's a path problem, but don't know that for sure. Is there a way to
get any output from 'command' either saved as a file on disk (I tried
appending &> file.txt, to no avail) or sent to a specific address? I
don't see any reply at the originator of the message or anything "odd"
in the logs on either system.

If I run the script outside of the exim environment, everything works
as expected...

Thanks in advance.

Bruce