Do not send a wall message before reboot/power-off (6/0)

Change SysV runlevel.
Since the concept SysV runlevels is obsolete the runlevel requests will be transparently translated into systemd unit activation requests.
More information: <https://manned.org/telinit>.
Trick copyright: tl;dr; <https://github.com/tldr-pages/tldr>

telinit --no-wall {{value}}

click the source code to copy install telinit on any operating system with command-not-found.com