That is a very interesting idea! It is not something we've discussed before as far as I know. For some utils (like chmod) it might be possible, but any util that is focused on outputting information currently does so by printing directly to stdout. So, ls doesn't give you a Vec or Iterator of listed files for instance, but instead prints them to stdout. Nevertheless, it would be a cool experiment to see if we can create something like a "ulib" crate that would provide the functions some functions for which it is possible.

I believe I actually had a proof of concept of this functionality in a PR at some point. This would basically have to work like mesabox, where each utility takes some generic input and output and then runs based on them rather than using stdout and friends directly (e.g. to avoid blowing through all your memory by stuffing many gigabytes of output into a Vec on certain commands).

That would be much more elegant than something like libxo.