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Re: Real difference between shutdown(8) and poweroff (8)

> > what'is the real difference between:shutdown(8),
> > poweroff(8),reboot(8) and halt(8) ?
> The shutdown tool is setuid root and only executable
> by root or members of 
> the operator group (so runs with root privilege). It
> can be used to set 
> when a shutdown should happen. It runs in the
> background, logs about the 
> shutdown, and sends shutdown messages to the
> terminals of current logins 
> (using wall) warning when the shutdown will happen.
> If the shutdown time 
> is within five minutes it creates a /etc/nologin
> file which is honored by 
> login, sshd, and a PAM module to prevent new logins.
> Then shutdown runs 
> the /etc/rc.shutdown script. Basically that script
> runs the rc.d scripts 
> containing the "shutdown" keyword in reverse order
> with the "stop" command 
> line argument. And then shutdown runs halt (or
> reboot).
> The halt, reboot, and poweroff tools are just the
> same command. It will 
> log to the wtmp and wtmpx login databases about the
> shutdown or reboot, do 
> a sync so pending disk writes are completed, kill
> init, send a SIGTERM to 
> all non-kernel processes, waits two seconds, does a
> sync again, waits 
> three more seconds, sends an uncatchable SIGKILL to
> all processes (and 
> retries that if needed a couple times), and then
> reboots the system or 
> halts the processor(s).
> Running poweroff will power off the hardware (on
> supported systems).
> (I have more details in my NetBSD book in process.)
My goal is to write a software GUI/GNOME for netbsd,
which supports the commands: shutdown,
poweroff,reboot, halt 



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