demux is a utility to split up the lines of a file into several
different files. It takes /n/ regular expressions and /n/ output
files, and it puts each line of input into the file that corresponds
to the first matching regular expression.
(This differs from the standard csplit utility in that the patterns
denote which file the line should go into instead of the points where
the input should be split.)
There isn't any. Just copy src/demux.py into your path somewhere,
and rename it to just demux if you wish. Or leave it where it is now
and just specify the path.
See the included manpage (you can view it with, e.g., less) for
usage information.