And here goes my first "real" post on Steemit. Aimed on Linux users (mainly Debianers) :)
There is a problem with recent Debian's release (called "Jessie") which using systemd as init system - when you type "reboot" or "shutdown" in SSH session - your server isn't disconnecting you and you have to close terminal window/tab or wait until SSH "understands" that server goes down. But there is a way to fix it :)
You have to install PAM module which will "talk" with systemd:
apt-get install libpam-systemd
After that you should add one line to /etc/pam.d/common-session
:
session optional pam_systemd.so
After reboot your server will disconnect you when you will try to reboot/shutdown it.
thank you, @pztrn!