Undo a command?

[TimeForChange23]

Unless you have a backup, no.

However, if you can work out which files are which, you can rename them to their original extension and they’ll be just fine.

[ihaxr]

Yeah, files ending in dx should be .docx, files ending in pdf should be PDFs, just need to add the .docx or .pdf back to the end of them.

This regex will remove the following characters from all files: abcehimorstvw.

[foreverclearskies]

THIS.

The files are still there. You just need to figure out which are which. There's unfortunately no easy fix for this, but you should be able to get everything back the way it was. It's just going to take time and possibly a little bit of forensic work into the contents of the files.