Show HN: DatePrefixCopy, prefixing file names with yymmdd_
Windows-only, written in Lisp. Reasoning: some companies do that for "version control". They all use Windows. This is a zero-click solution.
The code looks pretty readable, if you're familiar with CL and the Windows API - nice!
You might want to consider not :USEing your dependencies, and use the package name prefix when you invoke exported symbols instead, though, like you did with re.
Speaking of which, is re this: https://github.com/massung/re?