What is the primary function of the 'shutdown' command?

The primary function of the 'shutdown' command is to shut down or reboot the system. This command is widely used to safely bring down the operating system, ensuring that all processes are terminated properly and that the filesystem is unmounted cleanly.

When executed, the 'shutdown' command can either power off the machine or restart it, depending on the options specified. For example, using 'shutdown now' will immediately halt the system, while 'shutdown -r now' will reboot the system right away. This is crucial for maintaining system integrity and preventing data loss or corruption.

In different situations, administrators may choose to schedule a shutdown to allow users to save their work or to perform maintenance tasks during off-peak hours, showcasing the versatility and importance of this command in system management.