In linux, the -u parameter will not work as it is reliant upon the parameter matching to a linux account name. I have been trying to figure out why the spam identification has been very poor and was able to isolate it down to that parameter.
I have removed this parameter and will report back on the spam scoring to see if there is any improvement.
As a side note, linux is capable of using per user configurations, however, an SQL (most likely MySQL), will need to be set up for bypassing the local account name lookup.