Hi guys,

Can anybody please help me to understand the differences between the
system boot commands..... Like when and why should we use reboot
command or init 6 or shutdown etc...etc..??

Thanks in advance...


-Vinu.

"vinsidus@gmail.com" <vinsidus@gmail.com> writes:

> Can anybody please help me to understand the differences between the
> system boot commands..... Like when and why should we use reboot
> command or init 6 or shutdown etc...etc..??

halt(1M) brings down the machine to the PROM (on SPARC) immediately,
with very little regard to running the scripts in /etc/rc[0-6].d to
take things down cleanly. reboot(1M) is the same, except instead of
just stopping the OS, it reboots the machine.

init(1M) would run the scripts in /etc/rc[0-6].d to (hopefully) take
down the running processes cleanly, and then call halt, reboot, or
poweroff(1M) depending on the argument you give it.

shutdown(1M) allows you to first give a time when the machine will
shutdown, prints warnings to users logged in (and possibly to any NFS
clients), and then calls init(1M). init then does things like
described in the above paragraph.

Using shutdown or init is usually the best way to go about things
AFAIK.

I try to keep in the habit of using shutdown(1M) since by default it
gives a grace period before doing things. This way if you're /not/ on
the machine you think you are (you're on production, and not a testing
server), you still have an opportunity to cancel things before
accidentally disrupting service.

--
David Magda <dmagda at ee.ryerson.ca>
Because the innovator has for enemies all those who have done well under
the old conditions, and lukewarm defenders in those who may do well
under the new. -- Niccolo Machiavelli, _The Prince_, Chapter VI