著者: Brad Campbell 日付: To: dng 題目: Re: [DNG] F1 and special usernames on the login screen
On 19/07/16 00:37, Steve Litt wrote: > Hi all, > SPECIAL USERNAMES
>
> The login screen has no controls other than the input field. So how do
> you reboot, halt or go to a console from the login screen? The answer
> is, you use a special username.
>
> For instance, to reboot the computer from the login screen, type in the
> username "reboot" (without the quotes), then when asked for the
> password put the root password, and it reboots. If you want to halt,
> use the username "halt". To go to a console, use "console" without any
> password. A little console appears, asking you for username and
> password. When you exit the console via the exit command or Ctrl+d on
> the console, you go back to the login screen.
This is one I find interesting. I've never used an operating system
where it was required to know root credentials to halt or reboot the
machine from the login screen. Certainly if the machine is logged in but
locked, unlocking is required first but on any of the other OS I use I
can simply shutdown or reboot unauthenticated.
A good example is my desktop. It's an iMac and it triple boots OSX,
Windows & Linux. Now, it only gets rebooted every year or so for a
kernel update or if I need to spark up OSX to test something specific.
If I reboot the machine and am not there to hold the magic keys required
for it to boot to linux, it winds up at the OSX login screen. From there
I can simply click reboot and away we go. Why should I need to know the
root login to do that?
As for root logins on my machines. They all have 16 character randomly
generated passwords that are all but impossible to remember. The only
time I actually need a root password is if something catastrophic
happens and I need to access the rescue console. Everything else is
managed with sudo. When I do need the root password I can look it up in
my password wallet. I've had to do that precisely 3 times in the last 6
years.
So all that rambling comes back to "why do I need to know my root
password to halt or reboot the machine from the login screen?"