Here are some very basic filter scripts that could be used with the 
FileFilter configuration directive.

In general, Swish-e's FileFilter feature is best used with binary programs 
to avoid the time parsing and compiling a script for each document that 
needs to be filtered.

    _binfilter.sh
        This filter uses the strings(1) command to extract
        text out of binary files.
        

    _pdf2html.pl
        Filter uses the xpdf package's programs pdfinfo and pdftotext
        to convert a PDF file into html.


    swish_filter.pl
        Uses the SWISH::Filter module to filter a number of different types
        of documents with the same script.