UNIX for Advanced & Expert Users

You lost your bet, achenle

Code:

# dd if=/dev/zero of=/proc/1/as
dd: /proc/1/as: open: Permission denied
# uname -a
SunOS sol10 5.10 Generic_141445-09 i86pc i386 i86pc

I agree completely with Corona688 (post#4). You can't mess with the init process!!!!

The init process is part of the kernel (PID=1) and all you are doing with 'init 6' is sending a signal to that process to change run level.

Direct use of the init command gets a faster response than the shutdown command and is often used by sysadmins. However, you need root privs to get the command acted on by the system and, if you are logged in as root (or su'd to root), you need to be thinking about what you're doing VERY CAREFULLY. Root bypasses all normal security on most Unix flavors, you are god and anything you say goes, no questions asked. There are all sorts of commands that root can accidentally type that will completely destroy the system outright.

If I login on my own account then I know that if I try something stupid that the system will tell me. If I login as root then I really pay attention to what I'm doing (and logout from root as soon as possible).

Taking the question literally, this is actually very easy to do. Wait until the system has shut down and then power it off. That will stop the reboot.

I'm not just being a wiseguy. I have done exactly this several times in the past several years. I meant to type "init 5" and accidentally typed "init 6". These were servers on my desk and I was re-installing (an upgraded version of) the OS. So I had easy access to the power button.