This recipe shuts down the Linux operating systems so that the Raspberry Pi can be powered off safely.
Before powering down the Raspberry Pi, it is important to first shut down the operating system so that all of the applications and services on the Raspberry Pi have completely finished writing to disk and are ready for the next boot.
External devices, such as hard disks, also need time to shut down and flush their buffers. The
shutdown command also gives devices attached to the Raspberry Pi an opportunity to clean up and prepare for the next boot.
The following are the ingredients:
- An initial Raspberry Pi setup (see the Preparing for the initial boot recipe)
- An SD card formatted with the official Raspbian Linux image
The Raspberry Pi should already be powered on and booted before starting with this recipe.
The following are the steps for shutting down the Raspberry Pi:
- Log in to the Raspberry Pi with
pias the username (the default password israspberry).
The preceding screenshot shows the process of logging in to the Raspberry Pi with
pias the username. - Execute the following command:
shutdown –h now
Shut down and halt the operating system. This command is privileged. Use the prefix
sudoto run theshutdowncommand as a privileged user.
The preceding screenshot shows how to shut down the Raspberry Pi.
- The Raspberry Pi will begin to shut down, displaying messages from applications, devices, and services as they clean up and prepare for the next boot.
- Once the operating system has shut down, the Raspberry Pi will halt. Only a single red LED will remain lit on the Raspberry Pi as the Raspberry Pi is still powered on. The main display will be blank.
- The power to the Raspberry Pi can now be shut off.
Once the Raspberry Pi boots, it prompts for a username and a password. By default, the Raspbian Linux distribution has one user configured, the pi user. This user's default password is raspberry. The password for the pi user can be changed using the raspi-config command.
After login, the shutdown command is executed with the –h option telling the Raspberry Pi to halt the system (power it off) after the operating
system has shut down. The shutdown command is privileged, so the sudo command is used as a prefix to temporarily grant privileges.
The shutdown command can also be used to reboot the system. Use the –r option. Rebooting the system when logged in as the pi user can be done with the following command:
sudo shutdown –r now
A number of synonyms exist for the shutdown command including halt, poweroff, 'and reboot.
- halt, reboot, poweroff – stop the system
http://manpages.debian.net/cgi-bin/man.cgi?query=halt
- shutdown – bring the system down