/usr/bin/cupsfilter: Error - unknown option "--".
Usage: cupsfilter [ options ] [ -- ] filename
Options:
  --list-filters          List filters that will be used.
  -D                      Remove the input file when finished.
  -P filename.ppd         Set PPD file.
  -U username             Specify username.
  -c cups-files.conf      Set cups-files.conf file to use.
  -d printer              Use the named printer.
  -e                      Use every filter from the PPD file.
  -i mime/type            Set input MIME type (otherwise auto-typed).
  -j job-id[,N]           Filter file N from the specified job (default is file 1).
  -m mime/type            Set output MIME type (otherwise application/pdf).
  -n copies               Set number of copies.
  -o name=value           Set option(s).
  -p filename.ppd         Set PPD file.
  -t title                Set title.
  -u                      Remove the PPD file when finished.