There is probably some bug (but i don't know, if it isn't my fault),
because if i give to command line
interwiki.py -cat:category -force -start:f -subcat
it asks me for name of category and then starts from first page (e. g.
[]) instead of [[F]]. When i change position of parameters, sometimes
it start from allpages.
When i exclude -start:xxx, it asks me for name of category too.