in reply to file i/o beyond my knowledge

None of this is actualy complicated. It's all a matter of taking a bunch of simple things and putting them together.

"Prompt the user for a directory": print, <>.

"Read the files from that directory": glob('*'), or opendir(), readdir(), ...

"Create a sub-directory": mkdir

"copy all the files into that sub directory": `cp`, or open, etc, etc

Warning: Unless otherwise stated, code is untested. Do not use without understanding. Code is posted in the hopes it is useful, but without warranty. All copyrights are relinquished into the public domain unless otherwise stated. I am not an angel. I am capable of error, and err on a fairly regular basis. If I made a mistake, please let me know (such as by replying to this node).

In Section Seekers of Perl Wisdom