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Suppose I have 20 process/deqamons running in my linux system, How different the HALT will have an effect on my process/deamons, when compared to a normal shutdown..,

*Note: I need to understand..one of my device proc fails to react for ioctl calls midst while using the shutdown -h command, But works properly in case of shutdown -r reboot option..,

marked as duplicate by RalfFriedl, Romeo Ninov, Thomas, John WH Smith, steve Sep 9 '18 at 14:26

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shutdown schedules a time for the system to be powered down. It may be used to halt, power-off or reboot the machine.

shutdown -h

is equivalent to : shutdown --poweroff simply it means POWEROFF.

in the other hand

shutdown -H


shutdown --halt

instructs the hardware to stop all CPU functions, but leaves it powered on. You can use it to get the system to a state where you can perform low level maintenance. Note that in some cases it completely shuts down the system. Below are examples of halt

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