[matthewmc3]

As far as I can tell with oils, they haven't fully defined what YSH is going to be yet - you basically have OSH (the bash compatibility syntax), with the option to add YSH features as a bolt on. It'd be like Zsh shipping with a built-in Fish-mode to create hybrid scripting. The interesting thing with shells like Xonsh and now rubish is that theoretically the shell language isn't some new thing you have to learn like with elvish and nushell, but is a known programming language with shell features. Rubish looks like it takes the most interesting parts of Oils and Xonsh, in that it's bash compatible, but you could also do a Ruby statement like `ls.each { |f| printf "%s: %d bytes\n", f, File.size(f) }`.