In Pelican 3.5 I know I can sort articles by attributes, like
ARTICLE_ORDER_BY = 'title'
but I would like to order by the filename. It is much easier to change the filenames than to open each file and edit the attributes.
Try this:
ARTICLE_ORDER_BY = 'filename'
or
ARTICLE_ORDER_BY = lambda x:os.path.basename(x.source_path or '')