If someone is remotely connected to my single ARM board computer with Debian 32-bit OS, (example: thru hijacking the browser), which connects through a firewall on a separate Orange Pi board, and I run shutdown, I have been told that the remote users/ hackers will “immediately” be disconnected from my computer and they can't see what I do before shutdown completes in the next 60 seconds.
1) In order for the first premise to ring true, do I need to be in admin “#”, for example: # shutdown ?
2) After reading more, it seems that by NOT including “-h” (shutdown -h now) it does not actually halt the system; it still allows the administrator to remain logged in as root. If I omit the -h, will the remote hackers still be disconnected immediately with just shutdown now?
3) If I type shutdown +90, will the remote hackers be disconnected immediately, and then for the next 90 minutes as well?