Given that I'm guaranteed to forget that I have this thing installed if I would install it, I'm just going to steal the idea and try to remember to use my editor instead of an ugly shell loop next time I want to rename many files. There's only a small difference, really, between transforming `1.txt 2.txt 3.txt` to `file1.md file2.md file3.md` and transforming to `mv 1.txt file1.md; mv 2.txt file2.md; mv 3.txt file3.md`.