Should CLI (command line interface) have a nice UI library?There are many. The generic underlying library is usually ncurses.
But it needs to be stressed that there are many. For Python there is Textualize [1], for Go there is Charm [2], rust has a TUI crate [3] among other options.
Also, OP might be interested in this list of "Modern Unix" tools. [4] Cheers, Tom [1] https://www.textualize.io [2] https://github.com/charmbracelet [3] https://docs.rs/tui/latest/tui/ [4] https://github.com/ibraheemdev/modern-unix