Any Operating Systems that make use of JavaScript?
Are there any operating systems that make use of JavaScript as a command line environment or shell scripting language?
No, because it’s a terrible idea. She’ll languages are uniquely different for a reason. And while there is room for improvement, wholesale replacement by JavaScript is not that.
I think that Tizen and Firefox os used js and html 5 for their interfaces but it is a faid memory, haven't checked it to confirm.
GNOME Desktop Environment uses it for shell extensions. So yeah, there are - kinda sorta.
webOS in the Palm/HP era had most apps and parts of the shell written in JavaScript, don't know if LG kept the framework or how it evolved.