define helps you create 'define.pdf' and associated file tree for FDA-style submission of analysis datasets, etc. It converts csv files to SAS Transport V. 5 'xpt' format, using metadata encoded in a specification file. It enforces the 'txt' extension for other (presumably ASCII) files.
The only function you're likely to need from define is
define
. You may want to learn more about
metadata encoding from encode and more about
specification files from spec.